N-(aryl/heteroaryl) amino acid derivatives, pharmaceutical compositions comprising same, and methods for inhibiting β-amyloid peptide release and/or its synthesis by use of such compounds

ABSTRACT

Disclosed are compounds which inhibit β-amyloid peptide release and/or its synthesis, and, accordingly, have utility in treating Alzheimer&#39;s disease. Also disclosed are pharmaceutical compositions comprising a compound which inhibits β-amyloid peptide release and/or its synthesis as well as methods for treating Alzheimer&#39;s disease both prophylactically and therapeutically with such pharmaceutical compositions.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation, of Application Ser. No. 08/976,191,filed Nov. 21, 1997, now U.S. Pat. No. 6,096,782.

This application claims the benefit of U.S. Provisional Application No.60/077,175, which was converted pursuant to 37 C.F.R. § 1.53(b)(2)(ii)from U.S. patent application Ser. No. 08/755,334, filed Nov. 22, 1996,which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to compounds which inhibit β-amyloid peptiderelease and/or its synthesis, and, accordingly, have utility in treatingAlzheimer's disease. This invention also relates to pharmaceuticalcompositions comprising such compounds as well as methods for inhibitingrelease of β-amyloid peptide.

2. References

The following publications, patents and patent applications are cited inthis application as superscript numbers:

¹ Glenner, et al., “Alzheimer's Disease: Initial Report of thePurification and Characterization of a Novel Cerebrovascular AmyloidProtein”, Biochem. Biophys. Res. Commun., 120:885-890 (1984).

² Glenner, et al., “Polypeptide Marker for Alzheimer's Disease and itsUse for Diagnosis”, U.S. Pat. No. 4,666,829 issued May 19, 1987.

³ Selkoe, “The Molecular Pathology of Alzheimer's Disease”, Neuron,6:487-498 (1991).

⁴ Goate, et al., “Segregation of a Missense Mutation in the AmyloidPrecursor Protein Gene with Familial Alzheimer's Disease”, Nature,349:704-706 (1990).

⁵ Chartier-Harlan, et al. “Early-Onset Alzheimer's Disease Caused byMutations at Codon 717 of the β-Amyloid Precursor Protein Gene”, Nature,353:844-846 (1989).

⁶ Murrell, et al., “A Mutation in the Amyloid Precursor ProteinAssociated with Hereditary Alzheimer's Disease”, Science, 254:97-99(1991).

⁷ Mullan, et al., “A Pathogenic Mutation for Probable Alzheimer'sDisease in the APP Gene at the N-Terminus of β-Amyloid, Nature Genet.,1:345-347 (1992).

⁸ Schenk, et al., “Methods and Compositions for the Detection of Solubleβ-Amyloid Peptide”, International Patent Application Publication No. WO94/10569, published May 11, 1994.

⁹ Selkoe, “Amyloid Protein and Alzheimer's Disease”, Scientfic American,pp. 2-8, November, 1991.

¹⁰ Yates, et al., “N,N-Disubstituted Amino Acid Herbicides”, U.S. Pat.No. 3,598,859, issued Aug. 10, 1971.

¹¹ Citron, et al., “Mutation of the β-Amyloid Precursor Protein inFamilial Alzheimer's Disease Increases β-Protein Production, Nature,360:672-674 (1992).

¹² Hansen, et al., “Reexamination and Further Development of a Preciseand Rapid Dye Method for Measuring Cell Growth/Cell Kill”, J. Immun.Meth., 119:203-210 (1989).

All of the above publications, patents and patent applications areherein incorporated by reference in their entirety to the same extent asif each individual publication, patent or patent application wasspecifically and individually indicated to be incorporated by referencein its entirety.

State of the Art

Alzheimer's Disease (AD) is a degenerative brain disorder characterizedclinically by progressive loss of memory, cognition, reasoning, judgmentand emotional stability that gradually leads to profound mentaldeterioration and ultimately death. AD is a very common cause ofprogressive mental failure (dementia) in aged humans and is believed torepresent the fourth most common irredical cause of death in the UnitedStates. AD has been observed in races and ethnic groups worldwide andpresents a major present and future public health problem. The diseaseis currently estimated to affect about two to three million individualsin the United States alone. AD is at present incurable. No treatmentthat effectively prevents AD or reverses its symptoms and course iscurrently known.

The brains of individuals with AD exhibit characteristic lesions termedsenile (or amyloid) plaques, amyloid angiopathy (amyloid deposits inblood vessels) and neurofibrillary tangles. Large numbers of theselesions, particularly amyloid plaques and neurofibrillary tangles, aregenerally found in several areas of the human brain important for memoryand cognitive function in patients with AD. Smaller numbers of theselesions in a more restrictive anatomical distribution are also found inthe brains of most aged humans who do not have clinical AD. Amyloidplaques and amyloid angiopathy also characterize the brains ofindividuals with Trisomy 21 (Down's Syndrome) and Hereditary CerebralHemorrhage with Amyloidosis of the Dutch Type (HCHWA-D). At present, adefinitive diagnosis of AD usually requires observing the aforementionedlesions in the brain tissue of patients who have died with the diseaseor, rarely, in small biopsied samples of brain tissue taken during aninvasive neurosurgical procedure.

The principal chemical constituent of the amyloid plaques and vascularamyloid deposits (amyloid angiopathy) characteristic of AD and the otherdisorders mentioned above is an approximately 4.2 kilodalton (kD)protein of about 39-43 amino acids designated the β-amyloid peptide(βAP) or sometimes Aβ, AβP or β/A4. β-Amyloid peptide was first purifiedand a partial amino acid sequence was provided by Glenner, et al.¹ Theisolation procedure and the sequence data for the first 28 amino acidsare described in U.S. Pat. No. 4,666,829².

Molecular biological and protein chemical analyses have shown that theβ-amyloid peptide is a small fragment of a much larger precursor protein(APP), that is normally produced by cells in many tissues of variousanimals, including humans. Knowledge of the structure of the geneencoding the APP has demonstrated that β-amyloid peptide arises as apeptide fragment that is cleaved from APP by protease enzyrne(s). Theprecise biochemical mechanism by which the β-amyloid peptide fragment iscleaved from APP and subsequently deposited as amyloid plaques in thecerebral tissue and in the walls of the cerebral and meningeal bloodvessels is currently unknown.

Several lines of evidence indicate that progressive cerebral depositionof β-amyloid peptide plays a seminal role in the pathogenesis of AD andcan precede cognitive symptoms by years or decades. See, for example,Selkoe³. The most important line of evidence is the discovery thatmissense DNA mutations at amino acid 717 of the 770-amino acid isoformof APP can be found in affected members but not unaffected members ofseveral families with a genetically determined (familial) form of AD(Goate, et al.⁴; Chartier Harlan, et al.⁵; and Murrell, et al.⁶) and isreferred to as the Swedish variant. A double mutation changinglysine⁵⁹⁵-methionine⁵⁹⁶ to asparagine⁵⁹⁵-leucine⁵⁹⁶ (with reference tothe 695 isoform) found in a Swedish family was reported in 1992 (Mullan,et al.⁷). Genetic linkage analyses have demonstrated that thesemutations, as well as certain other mutations in the APP gene, are thespecific molecular cause of AD in the affected members of such families.In addition, a mutation at amino acid 693 of the 770-amino acid isoformof APP has been identified as the cause of the β-amyloid peptidedeposition disease, HCHWA-D, and a change from alanine to glycine atamino acid 692 appears to cause a phenotype that resembles AD is somepatients but HCHWA-D in others. The discovery of these and othermutations in APP in genetically based cases of AD prove that alterationof APP and subsequent deposition of its β-amyloid peptide fragment cancause AD.

Despite the progress which has been made in understanding the underlyingmechanisms of AD and other β-amyloid peptide related diseases, thereremains a need to develop methods and compositions for treatment of thedisease(s). Ideally, the treatment methods would advantageously be basedon drugs which are capable of inhibiting β-amyloid peptide releaseand/or its synthesis.

SUMMARY OF THE INVENTION

This invention is directed to the discovery of a class of compoundswhich inhibit β-amyloid peptide release and/or its synthesis and,therefore, are useful in the prevention of AD in patients susceptible toAD and/or in the treatment of patients with AD in order to inhibitfurther deterioration in their condition. The class of compounds havingthe described properties are defined by formula I below:

wherein:

R¹ is selected from the group consisting of

(a) phenyl,

(b) a substituted phenyl group of formula II:

 wherein R^(c) is selected from the group consisting of acyl, alkyl,alkoxy, alkylalkoxy, azido, cyano, halo, hydrogen, nitro, trihalomethyl,thioalkoxy, and wherein R^(b) and R^(c) are fused to form a heteroarylor heterocyclic ring with the phenyl ring,

R^(b) and R^(b′) are independently selected from the group consisting ofhydrogen, halo, nitro, cyano, trihalornethyl, alkoxy, and thioalkoxywith the proviso that when R^(c) is hydrogen, then R^(b) and R^(b′) areeither both hydrogen or both substituents other than hydrogen,

(c) 2-naphthyl,

(d) 2-naphthyl substituted at the 4, 5, 6, 7 and/or 8 positions with 1to 5 substituents selected from the group consisting of alkyl, alkoxy,halo, cyano, nitro, trihalomethyl, thioalkoxy, aryl, and heteroaryl,

(e) heteroaryl, and

(f) substituted heteroaryl containing 1 to 3 substituents selected fromthe group consisting of alkyl, alkoxy, aryl, aryloxy, cyano, halo,nitro, heteroaryl, thioalkoxy and thioaryloxy provided that saidsubstituents are not ortho (adjacent) to the heteroaryl attachment tothe —NH group;

R² is selected from the group consisting of hydrogen, alkyl of from 1 to4 carbon atoms, alkylalkoxy of from 1 to 4 carbon atoms, alkylthioalkoxyof from 1 to 4 carbon atoms, aryl, heteroaryl, substituted aryl andsubstituted heteroaryl provided that the substituents are not ortho(adjacent) to the attachment of the aryl or heteroaryl atom to thecarbon atom;

R³ is selected from the group consisting of alkyl, alkenyl, alkynyl,aryl, cycloalkyl, cycloalkenyl, heteroaryl, substituted alkyl,substituted alkenyl, substituted alkynyl, and heterocyclic;

X is —C(O)Y where Y is selected from the group consisting of

(a) alkyl,

(b) substituted alkyl with the proviso that the substitution on saidsubstituted alkyl does not include α-haloalkyl, α-diazoalkyl orα-OC(O)alkyl groups,

(c) alkoxy or thioalkoxy,

(d) substituted alkoxy or substituted thioalkoxy,

(e) hydroxy,

(f) aryl,

(g) heteroaryl,

(h) heterocyclic,

(i) —NR′R″ where R′ and R″ are independently selected from the groupconsisting of hydrogen, alkyl, substituted alkyl, cycloalkyl, aryl,heteroaryl, heterocyclic, and where R′ and R″ are joined to form acyclic group having from 2 to 8 carbon atoms optionally containing 1 to2 additional heteroatoms selected from the group consisting of oxygen,sulfur and nitrogen and optionally substituted with one or more alkyl oralkoxy groups, and

when R³ contains at least 3 carbon atoms, X can also be —CR⁴R⁴Y′ whereeach R⁴ is independently selected from the group consisting of hydrogen,alkyl, cycloalkyl, aryl, heteroaryl and heterocyclic and Y′ is selectedfrom the group consisting of hydroxyl, amino, thiol, —OC(O)R⁵, —SSR⁵,—SSC(O)R⁵ where R⁵ is selected from the group consisting of alkyl,substituted alkyl, cycloalkyl, aryl, heteroaryl and heterocyclic,

and with the proviso that when R¹ is 3,4-dichlorophenyl, R² is methyl,and R³ is benzyl derived from D-phenylalanine, then X is not —C(O)OCH₃.

Accordingly, in one of its method aspects, this invention is directed toa method for inhibiting β-amyloid peptide release and/or its synthesisin a cell which method comprises administering to such a cell an amountof a compound or a mixture of compounds of formula I above effective ininhibiting the cellular release and/or synthesis of β-anmyloid peptide.

Because the in vivo generation of β-amyloid peptide is associated withthe pathogenesis of AD^(8,9), the compounds of formula I can also beemployed in conjunction with a pharmaceutical composition toprophylactically and/or therapeutically prevent and/or treat AD.Accordingly, in another of its method aspects, this invention isdirected to a prophylactic method for preventing the onset of AD in apatient at risk for developing AD which method comprises administeringto said patient a pharmaceutical composition comprising apharmaceutically inert carrier and an effective amount of a compound ora mixture of compounds of formula I above.

In yet another of its method aspects, this invention is directed to atherapeutic method for treating a patient with AD in order to inhibitfurther deterioration in the condition of that patient which methodcomprises administering to said patient a pharmaceutical compositioncomprising a pharmaceutically inert carrier and an effective amount of acompound or a mixture of compounds of formula I above.

In formula I above, R¹ substituted phenyls are preferably 4-substituted,3,5-disubstituted or 3,4-disubstituted phenyl substituents wherein thesubstituents at the 3 and/or 5 positions are defined by R^(b), R^(b′) asabove and the substituents at the 4 position is defined by R^(c) asabove. Particularly preferred 3,5-disubstituted phenyls include, by wayof example, 3,5-dichlorophenyl, 3,5-difluorophenyl,3,5-di(trifluoromethyl)phenyl, 3,5-dimethoxyphenyl, and the like.Particularly, preferred 3,4-disubstituted phenyls include, by way ofexample, 3,4-dichlorophenyl, 3,4-difluorophenyl,3-(trifluoromethyl)-4-chlorophenyl, 3-chloro-4-cyanophenyl,3-chloro-4-iodophenyl, 3,4-methylenedioxyphenyl, and the like.Particularly preferred 4-substituted phenyls include, by way of example,4-azidophenyl, 4-bromophenyl, 4-chlorophenyl, 4cyanophenyl,4-ethylphenyl, 4-fluorophenyl, 4-iodophenyl, 4-(phenylcarbonyl)phenyl,4-(1-ethoxy)ethylphenyl, and the like.

Other preferred R¹ substituents include, by way of example, 2-naphthyl,quinolin-3-yl, 2-methylquinolin-6-yl, benzothiazol-6-yl,benzothiazol-2-yl, 5-indolyl, phenyl, 2-naphthyl, and the like.

Preferably R² is selected from the group consisting of alkyl of from 1to 4 carbon atoms, alkylalkoxy of from 1 to 4 carbon atoms,alkylthioalkoxy of from 1 to 4 carbon atoms, aryl, heteroaryl,substituted aryl and substituted heteroaryl provided that thesubstituents are not ortho to the attachment of the aryl or heteroarylatom to the carbon atom. Particularly preferred R² substituents include,by way of example, methyl, ethyl, n-propyl, iso-propyl, n-butyl,iso-butyl, —CH₂CH₂SCH₃, phenyl and the like.

Preferred R³ substituents include alkyl groups such as methyl, ethyl,n-propyl, iso-propyl, n-butyl, iso-bulyl, sec-butyl, and the like;substituted alkyl groups such as α-hydroxyethyl, —CH₂-cyclohexyl,benzyl, p-hydroxybenzyl, 3-iodo-4-hydroxybenzyl,3,5-diiodo-4-hydroxybenzyl, —CH₂-indol-3-yl, phenyl, —(CH₂)₄—NH-BOC,—(CH₂)₄—NH₂, —CH₂—(1-N-benzyl-imidazol-4-yl), —CH₂—imidazol-4-yl,—CH₂CH₂SCH₃, —(CH₂)₄NHC(O)(CH₂)₄CH₃, —(CH₂)_(y)C(O)OR⁵ where y is 1 or 2and R⁵ is hydrogen, methyl, tert-butyl, phenyl, and the like.

Preferred X substituents include —C(O)Y groups where Y is methoxy,ethyoxy, n-propoxy, iso-propoxy, n-butoxy, iso-butoxy, tert-butoxy,amino (—NH₂), N-(iso-butyl)amino, N-methylamino, N,N-dimethylamino,N-benzylamino, and the like as well as where X is —CH₂OH and the like.

This invention also provides for novel pharmaceutical compositionscomprising a pharmaceutically inert carrier and a compound of theformula I above.

Particularly preferred compounds for use in the methods and compositionsof this invention include, by way of example, the following wherein thestereochemistry of the R² and R³ groups is preferably derived from theL-amino acid:

N-[N-(3,4-dichlorophenyl)alanyl]valine methyl ester

N-[N-(3,4-dichlorophenyl)alanyl]valine N-iso-butyl amide

N-[N-(3,4-dichlorophenyl)alanyl]threonine methyl ester

N-[N-(3,4-dichlorophenyl)alanyl]valine ethyl ester

N-[N-(3,4-dichlorophenyl)alanyl]valine tert-butyl ester

N-[N-(3,4-dichlorophenyl)alanyl]valine amide

N-(3,4-dichlorophenyl)alanine N-(1-hydroxy-3-methyl-2-butyl) amide

N-[N-(3,4-dichlorophenyl)alanyl]valine N,N-dimethyl amide

N-[N-(3,4-dichlorophenyl)alanyl]valine N-methyl amide

N-[N-(3,4-dichlorophenyl)alanyl]alanine methyl ester

N-[N-(3,4-dichlorophenyl)alanyl]leucine methyl ester

N-[N-(3,4-dichlorophenyl)alanyl]phenylalanine methyl ester

N-[N-(3,4-dichlorophenyl)alanyl]isoleucine methyl ester

N-[N-(3,4-dichlorophenyl)alanyl]-2-aminopentanoic acid methyl ester

N-[N-(3,4-dichlorophenyl)alanyl]-2-aminohexanoic acid methyl ester

N-[N-(3,4-dichlorophenyl)alanyl]tryptophan methyl ester

N-[N-(3,4-dichlorophenyl)alinyl]aspartic acid α-methyl ester

N-[N-(3,4-dichlorophenyl)alanyl]aspartic acid β-(tert-butyl ester)α-methyl ester

N-[N-(3,4-dichlorophenyl)alinyl]-N-BOC-lysine methyl ester

N-[N-benzothiazol-6-yl)aianyl]-2-aminohexanoic acid methyl ester

N-[N-(3,4-dichlorophenyl)alanyl]lysine methyl ester

N-[N-(3,4-dichlorophenyl)alanyl]tyrosine methyl ester

N-[N-(3,5-dichlorophenyl)alanyl]alanine methyl ester

N-[N-(3,5-dichlorophenyl)alanyl]-2-aminopentanoic acid methyl ester

N-[N-(3,5-dichlorophenyl)alanyl]phenylalanine methyl ester

N-[N-(3,4-dichlorophenyl)alanyl]aspartic acid β-(methyl ester) α-methylester

N-[N-(3,4-dichlorophenyl)alanyl]-1-benzylhistidine methyl ester

N-[N-(3,4-dichlorophenyl)alanyl]glutamic acid γ-(tert-butyl ester)α-methyl ester

N-[N-(3,4-dichlorophenyl)alanyl]leucine amide

N-[N-(3,4-dichlorophenyl)alanyl]glutamic acid α-methyl ester

N-[N-(3,4-dichlorophenyl)alanyl]-(3,5-diiodo)tyrosine methyl ester

N-[N-(3,4-dichlorophenyl)alanyl]-(3-iodo)tyrosine methyl ester

N-[N-(3,5-dichlorophenyl)glycyl]-2-aminopentanoic acid methyl ester

N-[N-(3,4-dichlorophenyl)alanyl]-Nε-(hexanoyl)lysine methyl ester

N-[N-(3,4-dichlorophenyl)alanyl]phenylalanine amide

N-[N-(3,4-dichlorophenyl)alanyl]-2-aminohexan-(N-methyl)-amide

N-[N-(3,4-dichlorophenyl)alanyl]-βcyclohexylalanine methyl ester

N-[N-(3,4-dichlorophenyl)alanyl]-2-aminohexanamide

N-[N-(3,4-dichlorophenyl)alanyl]-2-aminohexan-(N,N-dimethyl)-amide

N-[N-(3,4-dichlorophenyl)alanyl]methionine methyl ester

N-[N-(3,5-dichlorophenyl)alanyl]-2-aminohexan-(N,N-dimethyl)-amide

N-[N-(3,5-dichlorophenyl)alanyl]-2-aminohexanamide

N-[N-(3,5-dichlorophenyl)alanyl]-2-aminohexan-(N-methyl)-amide

N-[N-(3,4-dichlorophenyl)alanyl]histidine methyl ester

N-[N-(quinolin-3-yl)alanyl]-2-aminohexanoic acid methyl ester

N-[N-(benzothiazol-2-yl)alanyl]2-aminohexanoic acid methyl ester

N-[N-(3,5-difluorophenyl)alanyl]alanine methyl ester

N-[N-(3,5-difluorophenyl)alanyl]-2-aminohexanoic acid methyl ester

N-[N-(3,4-dichlorophenyl)alanyl]-2-aminohexanamide

N-[N-(3,4-dichlorophenyl)alanyl]-2-aminohexan-(N-benzyl)-amide

N-[N-(3,4-dichlorophenyl)alanyl]-2-amino-2-phenylethanol

N-[N-(3,5-dichlorophenyl)phenylglycinyl]alanine methyl ester

N-[N-(3,4-dichlorophenyl)alanyl]-2-aminohexanol

N-[N-(3,5-dichlorophenyl)alanyl]-2-amino-2-phenylethanol

N-[N-(3,5-dichlorophenyl)alanyl]-phenylglycine tert-butyl ester

N-[N-(3,5-di-(trifluoromethyl)phenyl)alanyl]-phenylglycine tert-butylester

N-[N-(3,5-dimethoxyphenyl)alanyl]-2-aminohexanoic acid methyl ester

and pharmaceutically acceptable salts thereof.

Still further, this invention provides for novel compounds of theformula III:

wherein:

R¹ is selected from the group consisting of

(a) phenyl,

(b) a substituted phenyl group of formula II:

 wherein R^(c) is selected from the group consisting of acyl, alkyl,alkoxy, alkylalkoxy, azido, cyano, halo, hydrogen, nitro, trihalomethyl,thioalkoxy, and wherein R^(b) and R^(c) are fused to form a heteroarylor heterocyclic ring with the phenyl ring,

R^(b) and R^(b′) are independently selected from the group consisting ofhydrogen, halo, nitro, cyano, trihalomethyl, alkoxy, and thioalkoxy withthe proviso that when R^(c) is hydrogen, then R^(b) and R^(b′) areeither both hydrogen or both substituents other than hydrogen,

(c) 2-naphthyl,

(d) 2-naphthyl substituted at the 4, 5, 6, 7 and/or 8 positions with 1to 5 substituents selected from the group consisting of alkyl, alkoxy,halo, cyano, nitro, trihalomethyl, thioalkoxy, aryl, and heteroaryl,

(e) heteroaryl, and

(f) substituted heteroaryl containing 1 to 3 substituents selected fromthe group consisting of alkyl, alkoxy, aryl, aryloxy, cyano, halo,nitro, heteroaryl, thioalkoxy and thioaryloxy provided that saidsubstituents are not ortho to the heteroaryl attachment to the —NHgroup;

R² is selected from the group consisting of hydrogen, alkyl of from 1 to4 carbon atoms, alkylalkoxy of from 1 to 4 carbon atoms, alkylthioalkoxyof from 1 to 4 carbon atoms, aryl, heteroaryl, substituted aryl andsubstituted heteroaryl provided that the substituents are not ortho tothe attachment of the aryl or heteroaryl atom to the carbon atom;

R³ is selected from the group consisting of alkyl, alkenyl, alkynyl,aryl, cycloalkyl, cycloalkenyl, heteroaryl, substituted alkyl,substituted alkenyl, substituted alkynyl, and heterocyclic;

X is —C(O)Y where Y is selected from the group consisting of

(a) alkyl,

(b) substituted alkyl with the proviso that the substitution on saidsubstituted alkyl does not include α-haloalkyl, α-diazoalkyl orα-OC(O)alkyl groups,

(c) alkoxy or thioalkoxy,

(d) substituted alkoxy or substituted thioalkoxy,

(e) hydroxy,

(f) aryl,

(g) heteroaryl,

(h) heterocyclic,

(i) —NR′R″ where R′ and R″ are independently selected from the groupconsisting of hydrogen, alkyl, substituted alkyl, cycloalkyl, aryl,heteroaryl, heterocyclic, and where R′ and R″ are joined to form acyclic group having from 2 to 8 carbon atoms optionally containing 1 to2 additional heteroatoms selected from the group consisting of oxygen,sulfur and nitrogen and optionally substituted with one or more alkyl oralkoxy groups, and

when R³ contains at least 3 carbon atoms, X can also be —CR⁴R⁴Y′ whereeach R⁴ is independently selected from the group consisting of hydrogen,alkyl, cycloalkyl, aryl, heteroaryl and heterocyclic and Y′ is selectedfrom the group consisting of hydroxyl, amino, thiol, —OC(O)R⁵, —SSR⁵,—SSC(O)R⁵ where R⁵ is selected from the group consisting of alkyl,substituted alkyl, cycloalkyl, aryl, heteroaryl and heterocyclic,

and with the proviso that when R¹ is 3,4-dichlorophenyl, R² is methyl,and R³ is benzyl derived from D-phenylglycine, then X is not —C(O)OCH₃,

and still with the further proviso excluding the following knowncompounds:

when R¹ is phenyl, R² is methyl, X is —C(O)NHφ, then R³ is not methyl,iso-propyl, iso-butyl; and

when R¹ is phenyl, R² is methyl, X is —C(O)NH₂, then R³ is not benzyl.

Preferred compounds of formula III above include those set forth belowin Table I below:

TABLE I III

R¹ R² R³ X 3,4-dichlorophenyl —CH₃ —CH(CH₃)₂ —C(O)OCH₃3,4-dichloropheny1 —CH₃ —CH(CH₃)₂ —C(O)NHCH₂CH(CH₃)₂ 3,4-dichlorophenyl—CH₃ —CH(OH)CH₃ —C(O)OCH₃ 3,4-dichlorophenyl —CH₃ —CH(CH₃)₂ —C(O)OCH₂CH₃3,4-dichlorophenyl —CH₃ —CH(CH₃)₂ —C(O)OC(CH₃)₃ 3,4-dichlorophenyl —CH₃—CH(CH₃)₂ —C(O)NH₂ 3,4-dichlorophenyl —CH₃ —CH(CH₃)₂ —CH₂OH3,4-dichlorophenyl —CH₃ —CH(CH₃)₂ —C(O)N(CH₃)₂ 3,4-dichlorophenyl —CH₃—CH(CH₃)₂ —C(O)NHCH₃ 3,4-dichlorophenyl —CH₃ —CH₃ —C(O)OCH₃3,4-dichlorophenyl —CH₃ —CH₂CH(CH₃)₂ —C(O)OCH₃ 3,4-dichlorophenyl —CH₃—CH₂-φ —C(O)OCH₃ 3,4-dichlorophenyl —CH₃ —CH(CH₃)CH₂CH₃ —C(O)OCH₃3,4-dichlorophenyl —CH₃ —CH₂CH₂CH₃ —C(O)OCH₃ 3,4-dichlorophenyl —CH₃—(CH₂)₃CH₃ —C(O)OCH₃ 3,4-dichlorophenyl —CH₃ —CH₂-indol-3-yl —C(O)OCH₃3,4-dichlorophenyl —CH₃ —CH₂COOH —C(O)OCH₃ 3,4-dichlorophenyl —CH₃—CH₂C(O)O-tert-butyl —C(O)OCH₃ 3,4-dichlorophenyl —CH₃ —(CH₂)₄—NH—BOC—C(O)OCH₃ benzothiazol-6-yl —CH₃ —(CH₂)₃CH₃ —C(O)OCH₃ 3,4-dichlorophenyl—CH₃ —(CH₂)₄NH₂ —C(O)OCH₃ 3,4-dichlorophenyl —CH₃ p-hydroxybenzyl—C(O)OCH₃ 3,5-dichlorophenyl —CH₃ —CH₃ —C(O)OCH₃ 3,5-dichlorophenyl —CH₃—CH₂CH₂CH₃ —C(O)OCH₃ 3,5-dichlorophenyl —CH₃ —CH₂-φ —C(O)OCH₃3,4-dichlorophenyl —CH₃ —CH₂C(O)OCH₃ —C(O)OCH₃ 3,4-dichlorophenyl —CH₃—CH₂-(1-N-benzyl- —C(O)OCH₃ imidazol-4-yl) 3,4-dichlorophenyl —CH₃—(CH₂)₂C(O)O-tert-Bu —C(O)OCH₃ 3,4-dichlorophenyl —CH₃ —CH₂CH(CH₃)₂—C(O)NH₂ 3,4-dichlorophenyl —CH₃ —CH₂CH₂COOH —C(O)OCH₃3,4-dichlorophenyl —CH₃ —CH₂-(3,5-diiodo- —C(O)OCH₃ 4-hydroxyphenyl)3,4-dichlorophenyl —CH₃ —CH₂-(3-iodo- —C(O)OCH₃ 4-hydroxyphenyl)3,4-dichlorophenyl H —CH₂CH₂CH₃ —C(O)OCH₃ 3,4-dichlorophenyl —CH₃—(CH₂)₄NC(O)— —C(O)OCH₃ (CH₂)₄CH₃ 3,4-dichlorophenyl —CH₃ —CH₂-φ—C(O)NH₂ 3,4-dichlorophenyl —CH₃ —CH₂CH₂CH₂CH₃ —C(O)NHCH₃3,4-dichlorophenyl —CH₃ —CH₂-cyclohexyl —C(O)OCH₃ 3,4-dichlorophenyl—CH₃ —(CH₂)₃CH₃ —C(O)NH₂ 3,4-dichlorophenyl —CH₃ —(CH₂)₃CH₃ —C(O)N(CH₃)₂3,4-dichlorophenyl —CH₃ —CH₂CH₂SCH₃ —C(O)OCH₃ 3,5-dichlorophenyl —CH₃—CH₂CH₂CH₂CH₃ —C(O)N(CH₃)₂ 3,5-dichlorophenyl —CH₃ —CH₂CH₂CH₂CH₃—C(O)NH₂ 3,5-dichlorophenyl —CH₃ —CH₂CH₂CH₂CH₃ —C(O)NHCH₃3,4-dichlorophenyl —CH₃ —CH₂-imidazol-4-yl —C(O)OCH₃ quinolin-3-yl —CH₃—CH₂CH₂CH₂CH₃ —C(O)OCH₃ benzothiazol-2-yl —CH₃ —CH₂CH₂CH₂CH₃ —C(O)OCH₃3,5-difluorophenyl —CH₃ —CH₃ —C(O)OCH₃ 3,5-difluorophenyl —CH₃—CH₂CH₂CH₂CH₃ —C(O)OCH₃ 3,4-dichlorophenyl —CH₃ —CH₂CH₂CH₂CH₃ —C(O)NH₂3,4-dichlorophenyl —CH₃ —CH₂CH₂CH₂CH₃ —C(O)NHCH₂-φ 3,4-dichlorophenyl—CH₃ -φ —CH₂OH 3,5-dichlorophenyl -φ —CH₃ —C(O)OCH₃ 3,4-dichlorophenyl—CH₃ —CH₂CH₂CH₂CH₃ —CH₂OH 3,5-dichlorophenyl —CH₃ -φ —CH₂OH3,5-dichlorophenyl —CH₃ -φ —C(O)OC(CH₃)₃ 3,5-di-(trifluoro- —CH₃ -φ—C(O)OC(CH₃)₃ methyl)phenyl 3,5-dimethoxy- —CH₃ —CH₂CH₂CH₂CH₃ —C(O)OCH₃phenyl

DETAILED DESCRIPTION OF THE INVENTION

As above, this invention relates to compounds which inhibit β-amyloidpeptide release and/or its synthesis, and, accordingly, have utility intreating Alzheimer's disease. However, prior to describing thisinvention in further detail, the following terms will first be defined.

Definitions

The term “β-amyloid peptide” refers to a 39-43 amino acid peptide havinga molecular weight of about 4.2 kD which peptide is substantiallyhomologous to the form of the protein described by Glenner, et al.¹including mutations and post-translational modifications of the normalβ-amyloid peptide. In whatever form, the β-amyloid peptide isapproximately a 39-43 amino acid fragment of a large membrane-spanningglycoprotein, referred to as the β-amyloid precursor protein (APP). Its43-amino acid sequence is:

1 (SEQ ID NO: 1) Asp Ala Glu Phe Arg His Asp Ser Gly Tyr 11 Glu Val HisHis Gln Lys Leu Val Phe Phe 21 Ala Glu Asp Val Gly Ser Asn Lys Gly Ala31 Ile Ile Gly Leu Met Val Gly Gly Val Val 41 Ile Ala Thr

or a sequence which is substantially homologous thereto.

“Alkyl” refers to monovalent alkyl groups preferably having from 1 to 10carbon atoms and more preferably 1 to 6 carbon atoms. This term isexemplified by groups such as methyl, ethyl, n-propyl, iso-propyl,n-butyl, iso-butyl, n-hexyl, and the like.

“Substituted alkyl” refers to an alkyl group, preferably of from 1 to 10carbon atoms, having from 1 to 3 substituents selected from the groupconsisting of alkoxy, substituted alkoxy, acyl, acylamino, acyloxy,amino, aminoacyl, aminoacyloxy, cyano, halogen, hydroxyl, carboxyl,carboxylalkyl, cycloalkyl, oxyacylamino, thiol, thioalkoxy, substitutedthioalkoxy, aryl, heteroaryl, heterocyclic, nitro, and mono- anddi-alkylamino, mono- and di-(substituted alkyl)amino, mono- anddi-cycloalkylamino, mono- and di-arylamino, mono- anddi-heteroaryl-amino, mono- and di-heterocyclic amino, and unsymmetricdi-substituted aminries having different substituents selected fromalkyl, substituted alkyl, cycloalkyl, aryl, heteroaryl and heterocyclic.

“Alkylene” refers to divalent alkylene groups preferably having from 1to 10 carbon atoms and more preferably 1 to 6 carbon atoms. This term isexemplified by groups such as methylene (—CH₂—), ethylene (—CH₂CH₂—),the propylene isomers (e.g., —CH₂CH₂CH₂— and —CH(CH₃)CH₂—) and the like.

“Alkaryl” refers to -alkylene-aryl groups preferably having from 1 to 10carbon atoms in the alkylene moiety and from 6 to 10 carbon atoms in thearyl moiety. Such alkaryl groups are exemplified by benzyl, phenethyland the like.

“Alkoxy” refers to the group “alkyl-O-”. Preferred alkoxy groupsinclude, by way of example, methoxy, ethoxy, n-propoxy, iso-propoxy,n-butoxy, tert-butoxy, sec-butoxy, n-pentoxy, n-hexoxy,1,2-dimethylbutoxy, and the like.

“Substituted alkoxy” refers to the group “substituted alkyl-O-” wheresubstituted alkyl is as defined above.

“Alkylalkoxy” refers to the group “-alkylene-O-alkyl” where alkylene andalkyl are as defined above. Such groups include, by way of example,methylenemethoxy (—CH₂OCH₃), ethylenemethoxy (—CH₂CH₂OCH₃),n-propylene-iso-propoxy (—CH₂CH₂(,H₂OCH(CH₃)₂), methylene-tert-butoxy(—CH₂—O—C(CH₃)₃) and the like.

“Alkylthioalkoxy” refers to the group “-alkylene-S-alkyl” where alkyleneand alkyl are as defined above. Such groups include, by way of example,methylenethiomethoxy (—CH₂SCH₃), ethylenethiomethoxy (—CH₂CH₂SCH₃),n-propylene-iso-thiopropoxy (—CH₂CH₂CH₂SCH(CH₃)₂),methylenethio-tert-butoxy (—CH₂SC(CH₃)₃) and the like.

“Alkenyl” refers to alkenyl groups preferably having from 2 to 10 carbonatoms and more preferably 2 to 6 carbon atoms and having at least 1 andpreferably from 1-2 sites of alkenyl unsaturation. Preferred alkenylgroups include ethenyl (—CH═CH₂), n-propenyl (—CH₂CH═CH₂), iso-propenyl(—C(CH₃)═CH₂), and the like.

“Substituted alkenyl” refers to an alkenyl group as defined above havingfrom 1 to 3 substituents selected from the group consisting of alkoxy,substituted alkoxy, acyl, acylamino, acyloxy, amino, aminoacyl,aminoacyloxy, cyano, cycloalkyl, oxyacylamino, halogen, hydroxyl,carboxyl, carboxylalkyl, thiol, thioalkoxy, substituted thioalkzxy,aryl, heteroaryl, heterocyclic, nitro, and mono- and di-alkylamino,mono- and di-(substituted alkyl)amino, mono- and di-cycloalkyl, mono-and di-arylamino, mono- and di-heteroarylamino, mono- anddi-heterocyclic amino, and unsymmetric di-substituted amines havingdifferent substituents selected from alkyl, substituted alkyl,cycloalkyl, aryl, heteroaryl and heterocyclic.

“Alkynyl” refers to alkynyl groups preferably having from 2 to 10 carbonatoms and more preferably 2 to 6 carbon atoms and having at least 1 andpreferably from 1-2 sites of alkynyl unsaturation. Preferred alkynylgroups include ethynyl (—C≡CH), propargyl (—CH₂C≡CH) and the like.

“Substituted alkynyl” refers to an alkynyl group as defined above havingfrom 1 to 3 substituents selected from the group consisting of alkoxy,substituted alkoxy, acyl, acylamino, acyloxy, amino, aminoacyl,aminoacyloxy, cyano, cycloalkyl, oxyacylamino, halogen, hydroxyl,carboxyl, carboxylalkyl, thiol, thioalkoxy, substituted thioalkoxy,aryl, heteroaryl, heterocyclic, nitro, and mono- and di-alkylamino,mono- and di-(substituted alkyl)amino, mono- and di-cycloalkylamino,mono- and di-arylamino, mono- and di-heteroarylamino, mono- anddi-heterocyclic amino, and unsymmetric di-substituted amines havingdifferent substituents selected from alkyl, substituted alkyl,cycloalkyl, aryl, heteroaryl and heterocyclic.

“Acyl” refers to the groups alkyl—C(O)—, substituted alkyl—C(O)—,cycloalkyl—C(O)—, aryl—C(O)—, heteroaryl—C(O)— and heterocyclic—C(O)—where alkyl, substituted alkyl, cycloalkyl, arvl, heteroaryl andheterocyclic are as defined herein.

“Acylamino” refers to the group —C(O)NRR where each R is independentlyhydrogen, alkyl, substituted alkyl, cycloalkyl, aryl, heteroaryl. andheterocyclic and where each of alkyl, substituted alkyl, cycloalkyl,aryl, heteroaryl and heterocyclic are as defined herein.

“Aminoacyl” refers to the group —NRC(O)R where each R is independentlyhydrogen, alkyl, substituted alkyl, cycloalkyl, aryl, heteroaryl, andheterocyclic and where each of alkyl, substituted alkyl, cycloalkyl,aryl, heteroaryl and heterocyclic are as defined herein.

“Acyloxy” refers to the groups —OC(O)-alkyl, —OC(O)-substituted alkyl,—OC(O)-cycloalkyl, —OC(O)-aryl, —C(O)O-heteroaryl-, and—C(O)O-heterocyclic where alkyl, substituted alkyl, cycloalkyl, aryl,heteroaryl and heterocyclic are as defined herein.

“Aminoacyloxy” refers to the groups —NRC(O)O-alkyl, —NRC(O)O-substitutedalkyl, —NRC(O)O-cycloalkyl, —NRC(O)O-aryl, —NRC(O)O-heteroaryl-, and—NRC(O)O-heterocyclic where R is hydrogen, alkyl, substituted alkyl,cycloalkyl, aryl, heteroaryl, and heterocyclic and where each of alkyl,substituted alkyl, cycloalkyl, aryl, he,eroaryl and heterocyclic are asdefined herein.

“Oxyacylamino” refers to the groups —OC(O)NR-alkyl, —OC(O)NR-substitutedalkyl, —OC(O)NR-aryl, —OC(O)NR-heteroaryl-, and —OC(O)NR-heterocyclicwhere R is hydrogen, alkyl, substituted alkyl, cycloalkyl, aryl,heteroaryl, and heterocyclic and where each of alkyl, substituted alkyl,cycloalkyl, aryl, heteroaryl and heterocyclic are as defined herein.

“Aryl” refers to an unsaturated aromatic carbocyclic group of from 6 to14 carbon atoms having a single ring (e.g., phenyl) or multiplecondensed rings (e.g., naphthyl or anthryl). Preferred aryls includephenyl, naphthyl and the like.

Unless otherwise constrained by the definition for the aryl substituent,such aryl groups can optionally be substituted with from 1 to 3substituents selected from the group consisting of hydroxy, acyl,acyloxy, alkyl, substituted alkyl, alkoxy, substituted alkoxy, alkenyl,substituted alkenyl, alkynyl, substituted alkynyl, amino, aminoacyl,acylamino, aminoacyloxy, oxyacylamino, aryl, aryloxy, carboxyl,carboxylalkyl, cyano, halo, nitro, heteroaryl, trihalomethyl,thioalkoxy, substituted thioalkoxy, mono- and di-alkylamino, mono- anddi-(substituted alkyl)amino, mono- and di-cycloalkylamino, mono- anddi-arylainino, mono- and di-heteroarylamino, mono- and di-heterocyclicamino, and unsymmetric di-substituted amines having differentsubstituents selected from alkyl, substituted alkyl, cycloalkyl, aryl,heteroaryl and heterocyclic, and the like. Preferred substituentsinclude alkyl, alkoxy, halo, cyano, nitro, trihalomethyl, andthioalkoxy. When so substituted, such aryl groups are sometimes referredto herein as “substituted aryl”.

“Aryloxy” refers to the group aryl-O- wherein the aryl group is asdefined above including optionally SLubstituted aryl groups as alsodefined above.

“Carboxyalkyl” refers to the groups —C(O)O-alkyl and —C(O)O-substitutedalkyl where alkyl and substituted alkyl are as defined herein.

“Cycloalkyl” refers to cyclic alkyl groups of from 3 to 20 carbon atomshaving a single cyclic ring or multiple condensed rings (includingaromatic rings fused to the cycloalkyl ring) which can be optionallysubstituted with from 1 to 3 alkyl groups. Such cycloalkyl groupsinclude, by way of example, single ring structures such as cyclopropyl,cyclobutyl, cyclopentyl, cyclooctyl, 1-methylcyclopropyl,2-methylcyclopentyl, 2-methylcyclooctyl, and the like, or multiple ringstructures such as dibenzosuberane, adamantanyl, and the like.

“Cycloalkenyl” refers to cyclic alkenyl groups of from 4 to 8 carbonatoms having a single cyclic ring or multiple condensed rings and atleast one point of internal unsaturation which can be optionallysubstituted with from 1 to 3 alkyl groups. Examples of suitablecycloalkenyl groups include, for instance, cyclobut-2-enyl,cyclopent-3-enyl, cyclooct-3-enyl and the like.

“Halo” or “halogen” refers to fluoro, chloro, bromo and iodo andpreferably is either chloro or bromo.

“Heteroaryl” refers to a monovalent aromatic group of from 2 to 10carbon atoms and 1 to 4 heteroatoms selected from oxygen, nitrogen andsulfur within the ring.

Unless otherwise constrained by the definition for the heteroarylsubstituent, such heteroaryl groups can be optionally substituted with 1to 3 substituents selected from the group consisting of hydroxy, acyl,acyloxy, alkyl, substituted alkyl, alkoxy, substituted alkoxy, alkenyl,substituted alkenyl, alkynyl, substituted alkynyl, amino, aminoacyl,acylamino, aminoacyloxy, oxyacylamino, aryl, aryloxy, carboxyl,carboxylalkyl, cyano, halo, nitro, heteroaryl, trihalomethyl,thioalkoxy., substituted thioalkoxy, mono- and di-alkylamino, mono- anddi-(substituted alkyl)amino, mono- and di-cycloalkylamino, mono- anddi-arylamino, mono-and di-heteroarilamino, mono- and di-heterocyclicamino, and unsymmetric di-substituted amines having differentsubstituents selected from alkyl, substituted alkyl, cycloalkyl, aryl,heteroaryl and heterocyclic, and the like. Such heteroaryl groups canhave a single ring (e.g., pyridyl, furyl, etc.) or multiple condensedrings (e.g., indolizinyl or benzothienyl). Preferred heteroaryls includepyridyl, pyrrolyl, and furyl. When so substituted, such heteroarylgroups are sometimes referred to herein as “substituted heteroaryl”.

“Heterocycle” or “heterocyclic” refers to a monovalent saturated orunsaturated group having a single ring, or multiple condensed rings,from 1 to 12 carbon atoms and from 1 to 4 hetero atoms selected fromnitrogen, sulfur or oxygen within the ring.

Unless otherwise constrained by the definition for the heterocyclicsubstituent, such heterocyclic groups can be optionally substituted with1 to 3 substituents selected from the group consisting of hydroxy, acyl,acyloxy, alkyl, substituted alkyl, alkoxy, substituted alkoxy, alkenyl,substituted alkenyl, alkynyl, substituted alkynyl, amino, aminoacyl,acylamino, aminoacyloxy, oxyacylamino, aryl, aryloxy, carboxyl,carboxylalkyl, cyano, halo, nitro, heteroaryl, trihalomethyl,thioalkoxy, substituted thioalkoxy, mono- and di-alkylamino, mono- anddi-(substituted alkyl)amino, mono- and di-arylamino, mono-anddi-heteroarylamino, mono- and di-heterocyclic amino, and unsymmetricdi-substituted amines having different substituents selected from alkyl,substituted alkyl, cycloalkyl, aryl, heteroaryl and heterocyclic, andthe like. Such heterocyclic groups can have a single ring or multiplecondensed rings. Preferred heterocyclics include morpholino,piperidinyl, and the like.

Examples of heterocycles and heteroaryls include, but are not limitedto, furan, thiophene, thiazole, oxazole, pyrrole, imidazole, pyrazole,pyridine, pyrazine, pyrimidine, pyridazine, indolizine, isoindole,indole, indazole, purine, quinolizine, isoquinoline, quinoline,phthalazine, naphthylpyridine, quinoxaline, quinazoline, cinnoline,pteridine, carbazole, carboline, phenanthridine, acridine,phenanthroline, isothiazole, phenazine, isoxazole, phenoxazine,phenothiazine, imidazolidine, imidazoline, piperidine, piperazine,indoline, phthalimide, 1,2,3,4-tetrahydroisoquinoline,4,5,6,7-tetrahydrobenzo[b]thiophene, thiazole, thiazolidine, thiophene,benzo[b]thiophene, morpholino, piperidinyl, pyrrolidine,tetrahydrofuranyl, and the like.

“Thiol” refers to the group —SH.

“Thioalkoxy” refers to the group —S-alkyl.

“Substituted thioalkoxy” refers to the group —S-substituted alkyl.

“Thioaryloxy” refers to the group aryl-S— wherein the aryl group is asdefined above including optionally substituted aryl groups as alsodefined above.

“Thioheteroaryloxy” refers to the group heteroaryl-S— wherein theheteroaryl group is as defined above including optionally substitutedaryl groups as also defined above.

In the compounds of formula I, R^(b) and R^(c) can be fused to form aheteroaryl or heterocyclic ring with the phenyl ring. Fusion in thismanner results in a fused bicyclic ring structure of the formula:

where R′ is as defined above and A is the fused heteroaryl orheterocyclic group as these terms are as defined above wherein the twoatoms of the phenyl ring are included in the total atoms present in theheteroaryl or heterocyclic group. Examples of such fused ring systemsinclude, for instance, indol-5-yl, indol-6-yl, thionaphthen-5-yl,thionaphthen-6-yl, isothionaphthen-5-yl, isothionaphthen-6-yl,indoxazin-5-yl, indoxazin-6-yl, benzoxazol-5-yl, benzoxazol-6-yl,anthranil-5-yl, anthiranil-6-yl, quinolin-6-yl, quinolin-7-yl,isoquinolin-6-yl, isoquinolin-7-yl, cinnolin-6yl, cinnolin-7-yl,quinazolin-6yl, quinazolin-7-yl, benzofuran-5-yl, benzofuran-6-yl,isobenzofuran-5-yl, isobenzofuran-6-yl, and the like.

“Pharmaceutically acceptable salt” refers to pharmaceutically acceptablesalts of a compound of Formula I which salts are derived from a varietyof organic and inorganic counter ions well known in the art and include,by way of example only, sodium, potassium, calcium, magnesium, ammonium,tetraalkylammonium, and the like; and when the molecule contains a basicfunctionality, salts of organic or inorganic acids, such ashydrochloride, hydrobromide, tartrate, mesylate, acetate, maleate,oxalate and the like.

Compound Preparation

The compounds of formula I above are readily prepared via severaldivergent synthetic routes with the particular route selected relativeto the ease of compound preparation, the commercial availability ofstarting materials, and the like.

In one synthetic method, the R¹ group of the amino acid NH₂CH(R²)COOH oran ester thereof is first introduced onto the molecule. Afterwards,conventional coupling of the first R¹NHCH(R²)COOH or ester thereof withthe amine of NH₂CH(R³)C(O)Y provides for compounds of formula I whereinX is —C(O)Y.

Similarly, conventional reduction of the —C(O)Y group leads to —CH₂OHgroups and the like.

The introduction of the R¹ group onto the amino acid NH₂CH(R²)COOH orester thereof can be accomplished using several methods. For example,conventional coupling of a halo acetic acid with a primary amine formsan amino acid as shown in reaction (1) below:

wherein R¹ and R² are as defined above and X′ is preferably a halo groupsuch as chloro or bromo. Alternatively, leaving groups other than halomay be employed such as triflate, mesylate, tosylate and the like.Additionally, suitable esters of 1 may be employed in this reaction.

Reaction (1) involves coupling of a suitable haloacetic acid derivative1 with a primary aryl/heteroarylamine 2 under conditions which providefor amino acid 3. This reaction is described by, for example, Yates, etal.¹⁰ and proceeds by combining approximately stoichiometric equivalentsof haloacetic acid 1 with primary aryl/heteroarylamine 2 in a suitableinert diluent such as water, dimethylsulfoxide (DMSO) and the like. Thereaction employs an excess of a suitable base such as sodiumbicarbonate, sodium hydroxide, etc. to scavenge the acid generated bythe reaction. The reaction is preferably conducted at from about 25° C.to about 100° C. until reaction completion which typically occurs within1 to about 24 hours. This reaction is further described in U.S. Pat. No.3,598,859, which is incorporated herein by reference in its entirety.Upon reaction completion, N-aryl/N-heteroaryl amino acid 3 is recoveredby conventional methods including precipitation, chromatography,filtration and the like.

In reaction (1), each of the reagents (haloacetic acid 1, primaryaryl/heteroarylamine 2 and alcohol 3 are well known in the art with aplurality of each being commercially available.

In an alternative embodiment, the R¹ group can be coupled to an alanineester (or other suitable amino acid ester) by conventional N-arylation.For example, a stoichiometric equivalent or slight excess of the aminoacid ester can be dissolved in a suitable diluent such as DMSO andcoupled with a haloaryl compound, X-R¹ where X is a halo group such asfluoro, chloro or bromo and R¹ is as defined above. The reaction isconducted in the presence of an excess of base such as sodium hydroxideto scavenge the acid generated by the reaction. The reaction typicallyproceeds at from 15° C. to about 250° C. and is complete in about 1 to24 hours. Upon reaction completion, N-aryl amino acid ester is recoveredby conventional methods including chromatography, filtration and thelike.

In still another alternative embodiment, the esterified amino acids offormula I above can be prepared by reductive amination of a suitable2-oxocarboxylic acid ester (such as a pyruvate ester) in the mannerillustrated in Reaction (2) below:

wherein R¹ and R² are as defined above.

In reaction (2), approximately stoichiometric equivalents of a2-oxocarboxylic acid ester 6 and arylainine 2 are combined in an inertdiluent such as methanol, ethanol and the lilce and the reactionsolution treated under conditions which provide for imine formation (notshown). The imine formed is then reduced under conventional conditionsby a suitable reducing agent such as sodium cyanoborohydride,H₂/palladium on carbon and the like to form the N-aryl amino acid ester5. In a particularly preferred embodiment, the reducing agent isH₂/palladium on carbon which is incorporated into the initial reactionmedium which permits irvirte reduction in situ in a one pot procedure toprovide for the N-aryl amino acid ester 5.

The reaction is preferably conducted at from about 20° C. to about 80°C. at a pressure of from 1 to 10 atmospheres until reaction completionwhich typically occurs within 1 to about 24 hours. Upon reactioncompletion, N-aryl amino acid ester 5 is recovered by conventionalmethods including chromatography, filtration and the like.

Subsequent hydrolysis of the ester 5 leads to the correspondingcarboxylic acid derivative.

A further embodiment for preparing N-aryl amino acids includes aromaticnucleophilic substitution of fluorobenzenes by the amine group of anamino acid.

The carboxylic acid derivative 5 is then coupled under conventionalconditions well known in the art with a compound of the formulaNH₂CH(R³)C(O)Y where R³ and Y are as defined above. Such coupling leadsto compounds of formula I. Subsequent modifications (e.g., reduction)lead to further compounds of formula I.

When Y is an ester group, conventional transesterification techniquescan be used to prepare a variety of different ester groups on thecompounds of formula I. Numerous techniques are known in the art toeffect transesterification and each technique merely replaces the estergroup with a different ester group derived from the correspondingalcohol or thioalcohol and, in some cases, a catalyst such as titanium(IV) iso-propoxide is used to facilitate reaction completion. In onetechnique, the alcohol or thioalcohol is first treated with sodiumhydride in a suitable diluent such as toluene to form the correspondingsodium alkoxide or thioalkoxide which is then employed to effecttransesterification. The efficierncy of this technique makes itparticularly useful with high boiling and/or expensive alcohols.

In another transesterification technique, the ester to betransesterified is placed in a large excess of the alcohol orthioalcohol which effects transesterification. A catalytic amount ofsodium hydride is then added and the reaction proceeds quickly underconventional conditions to provide the desired transesterified product.Because this protocol requires the use of a large excess of alcohol orthioalcohol, this procedure is particularly useful when the alcohol isinexpensive.

Transesterification provides a lacile means to provide for amultiplicity of different ester substituents on the compounds of formulaI above. In all cases, the alcohols and thioalcohols employed to effecttransesterification are well known in the art with a significant numberbeing commercially available.

Other methods for preparing the esters of this invention include, by wayof example, first hydrolyzing the ester to the free acid followed byO-alkylation with, e.g., a haloalkyl group in the presence of a basesuch as potassium carbonate.

Still other methods for the preparation of compounds of formula I areprovided in the examples below.

Compounds where X is —CR⁴R⁴Y′ are readily prepared by coupling, e.g., anamino alcohol H₂NCHR³CR⁴R⁴OH, to the carboxyl group of R¹NHCHR²C(O)OHunder standard coupling conditions well known in peptide couplingchemistry which can use well known coupling reagents such as Scarbodiimides with or without the use of well known additives such asN-hydroxysuccinimide, 1-hydroxybenzotriazole, etc. If necessary, wellknown blocking groups on Y′ can be employred to protect the group duringcoupling. Such blocking groups are particularly desirable when Y′ is anamino group.

The reaction is conventionally conducted in an inert aprotic diluentsuch as dimethylformamide, dichloromethane, chloroform, acetonitrile,tetrahydrofuran and the like. Upon reaction completion, any blockinggroups on Y′ are selectively removed to provide for the desiredcompound.

When Y′ is —OH or —SH, post-synthetic conversion of these groups to thecorresponding esters (i.e., —OC(O)R⁵), disulfides (i.e., —SSR⁵) and—SSC(O)R⁵ groups is accomplished using well known chemistry. Forexample, ester synthesis requires only reaction with a suitable acidsuch as acetic acid (R⁷=methyl), acid halide (e.g., acid chloride) oracid anhydride under suitable esterification conditions.

When one of R⁴ groups is hydrogen, post-synthetic oxidation of the—CHR⁴OH group leads to the ketone derivatives. Alternatively, suchketones can be prepared by coupling the suitable aminoketone HCl saltwith the terminal carboxyl group of the amino acid.

In these synthetic methods, the starting materials can contain a chiralcenter (e.g., alanine) and, when a racemic starting material isemployed, the resulting product is a mixture of diastereomers or R,Senantiomers. Alternatively, a chiral isomer of the starting material canbe employed and, if the reaction protocol employed does not racemizethis starting material, a chiral product is obtained. Such reactionprotocols can involve inversion of the chiral center during synthesis.

Accordingly, unless otherwise indicated, the products of this inventionare a mixture of diastereomers (if two or more chiral centers arepresent) or R,S enantiomers (if only one chiral center is present).Preferably, however, when a chiral product is desired, the chiralproduct corresponds to the L-amino acid derivative. Alternatively,chiral products can be obtained via purification techniques whichseparates diastereomers or enantiomers from a R,S mixture to provide forone or the other stereoisomer. Such techniques are well known in theart.

Pharmaceutical Formulations

When employed as pharmaceuticals, the compounds of formula I are usuallyadministered in the form of pharmaceutical compositions. These compoundscan be administered by a variety of routes including oral, rectal,transdermal, subcutaneous, intravenous, intramuscular, and intranasal.These compounds are effective as both injectable and oral compositions.Such compositions are prepared in a manner well known in thepharmaceutical art and comprise at least one active compound.

This invention also includes pharmaceutical compositions which contain,as the active ingredient, one or more of the compounds of formula Iabove associated with pharmaceutically acceptable carriers. In makingthe compositions of this invention, the active ingredient is usuallymixed with an excipient, diluted by an excipient or enclosed within sucha carrier which can be in the form of a capsule, sachet, paper or othercontainer. When the excipient serves as a diluent, it can be a solid,semi-solid, or liquid material, which acts as a vehicle, carrier ormedium for the active ingredient. Thus, the compositions can be in theform of tablets, pills, powders, lozenges, sachets, cachets, elixirs,suspensions, emulsions, solutions, syrups, aerosols (as a solid or in aliquid medium), ointments containing, for example, up to 10% by weightof the active compound, soft and hard gelatin capsules, suppositories,sterile injectable solutions, and sterile packaged powders.

In preparing a formulation, it may be necessary to mill the activecompound to provide the appropriate particle size prior to combiningwith the other ingredients. If the active compound is substantiallyinsoluble, it ordinarily is milled to a particle size of less than 200mesh. If the active compound is substantially water soluble, theparticle size is normally adjusted by milling to provide a substantiallyuniform distribution in the formulation, e.g. about 40 mesh.

Some examples of suitable excipients include lactose, dextrose, sucrose,sorbitol, mannitol, starches, gum acacia, calcium phosphate, alginates,tragacanth, gelatin, calcium silicate, microcrystalline cellulose,polyvinylpyrrolidone, cellulose, sterile water, syrup, and methylcellulose. The formulations can additionally include: lubricating agentssuch as talc, magnesium stearate, and mineral oil; wetting agents;emulsifying and suspending agents; preserving agents such as methyl- andpropylhydroxybenzoates; sweetening agents; and flavoring agents. Thecompositions of the invention can be formulated so as to provide quick,sustained or delayed release of the active ingredient afteradministration to the patient by employing procedures known in the art.

The compositions are preferably formulated in a unit dosage form, eachdosage containing from about 5 to about 100 mg, more usually about 10 toabout 30 mg, of the active ingredient. The term “unit dosage forms”refers to physically discrete units suitable as unitary dosages forhuman subjects and other mammals, each unit containing a predeterminedquantity of active material calculated to produce the desiredtherapeutic effect, in association with a suitable pharmaceuticalexcipient. Preferably, the compound of formula I above is employed at nomore than about 20 weight percent of the pharmaceutical composition,more preferably no more than about 15 weight percent, with the balancebeing pharmaceutically inert carrier(s).

The active compound is effective over a wide dosage range and isgenerally administered in a pharmaceutically effective amount. It, willbe understood, however, that the amount of the compound actuallyadministered will be determined by a physician, in the light of therelevant circumstances, including the condition to be treated, thechosen route of administration, the actual compound administered, theage, weight, and response of the individual patient, the severity of thepatient's symptoms, and the like.

For preparing solid compositions such as tablets, the principal activeingredient is mixed with a pharmaceutical excipient to form a solidpreformulation composition containing a homogeneous mixture of acompound of the present invention. When referring to thesepreformulation compositions as homogeneous, it is meant that the activeingredient is dispersed evenly throughout the composition so that thecomposition may be readily subdivided into equally effective unit dosageforms such as tablets, pills and capsules. This solid preformulation isthen subdivided into unit dosage forms of the type described abovecontaining from, for example, 0.1 to about 500 mg of the activeingredient of the present invention.

The tablets or pills of the present invention may be coated or otherwisecompounded to provide a dosage form affording the advantage of prolongedaction. For example, the tablet or pill can comprise an inner dosage andan outer dosage component, the latter being in the form of an envelopeover the former. The two components can be separated by an enteric layerwhich serves to resist disintegration in the stomach and permit theinner component to pass intact into the duodenum or to be delayed inrelease. A variety of materials can be used for such enteric layers orcoatings, such materials including a number of polymeric acids andmixtures of polymeric acids with such materials as shellac, cetylalcohol, and cellulose acetate.

The liquid forms in which the novel compositions of the presentinvention may be incorporated for administration orally or by injectioninclude aqueous solutions, suitably flavored syrups, aqueous or oilsuspensions, and flavored emulsions with edible oils such as corn oil,cottonseed oil, sesame oil, coconut oil, or peanut oil, as well aselixirs and similar pharmaceutical vehicles.

Compositions for inhalation or insufflation include solutions andsuspensions in pharmaceutically acceptable, aqueous or organic solvents,or mixtures thereof, and powders. The liquid or solid compositions maycontain suitable pharmaceutically acceptable excipients as describedsupra. Preferably the compositions are administered by the oral or nasalrespiratory route for local or systemic effect. Compositions inpreferably pharmaceutically acceptable solvents may be nebulized by useof inert gases. Nebulized solutions may be inhaled directly from thenebulizing device or the nebulizing device may be attached to a facemask tent, or intermittent positive pressure breathing machine.Solution, suspension, or powder compositions may be administered,preferably orally or nasally, from devices which deliver the formulationin an appropriate manner.

The following formulation examples illustrate representativepharmaceutical compositions of the present invention.

FORMULATION EXAMPLE 1

Hard gelatin capsules containing the following ingredients are prepared:

Quantity Ingredient (mg/capsule) Active Ingredient 30.0 Starch 305.0Magnesium stearate 5.0

The above ingredients are mixed and filled into hard gelatin capsules in340 mg quantities.

FORMULATION EXAMPLE 2

A tablet formula is prepared using the ingredients below:

Quantity Ingredient (mg/tablet) Active Ingredient 25.0 Cellulose,microcrystalline 200.0 Colloidal silicon dioxide 10.0 Stearic acid 5.0

The components are blended and compressed to form tablets, each weighing240 mg.

FORMULATION EXAMPLE 3

A dry powder inhaler formulation is prepared containing the followingcomponents:

Ingredient Weight % Active Ingredient  5 Lactose 95

The active ingredient is mixed with the lactose and the mixture is addedto a dry powder inhaling appliance.

FORMULATION EXAMPLE 4

Tablets, each containing 30 mg of active ingredient, are prepared asfollows:

Quantity Ingredient (mg/tablet) Active Ingredient 30.0 mg Starch 45.0 mgMicrocrystalline cellulose 35.0 mg Polyvinylpyrrolidone  4.0 mg (as 10%solution in sterile water) Sodium carboxymethyl starch  4.5 mg Magnesiumstearate  0.5 mg Talc  1.0 mg Total  120 mg

The active ingredient, starch and cellulose are passed through a No. 20mesh U.S. sieve and mixed thoroughly. The solution ofpolyvinylpyrrolidone is mixed with the resultant powders, which are thenpassed through a 16 mesh U.S. sieve. The granules so produced are driedat 50° to 60° C. and passed through a 16 mesh U.S. sieve. The sodiumcarboxymethyl starch, magnesium stearate, and talc, previously passedthrough a No. 30 mesh U.S. sieve, are then added to the granules which,after mixing, are compressed on a tablet machine to yield tablets eachweighing 120 mg.

FORMULATION EXAMPLE 5

Capsules, each containing 40 mg of medicament are made as follows:

Quantity Ingredient (mg/capsule) Active Ingredient  40.0 mg Starch 109.0mg Magnesium stearate  1.0 mg Total 150.0 mg

The active ingredient, starch, and magnesium stearate are blended,passed through a No. 20 mesh U.S. sieve, and filled into hard gelatincapsules in 150 mg quantities.

FORMULATION EXAMPLE 6

Suppositories, each containing 25 mg of active ingredient are made asfollows:

Ingredient Amount Active Ingredient   25 mg Saturated fatty acidglycerides to 2,000 mg

The active ingredient is passed through a No. 60 mesh U.S. sieve andsuspended in the saturated fatty acid glycerides previously melted usingthe minimum heat necessary. The mixture is then poured into asuppository mold of nominal 2.0 g capacity and allowed to cool.

FORMULATION EXAMPLE 7

Suspensions, each containing 50 mg of medicament per 5.0 mL dose aremade as follows:

Ingredient Amount Active Ingredient 50.0 mg Xanthan gum  4.0 mg Sodiumcarboxymethyl cellulose (11%) 50.0 mg Microcrystalline cellulose (89%)Sucrose 1.75 g Sodium benzoate 10.0 mg Flavor and Color     q.v.Purified water to  5.0 mL

The active ingredient, sucrose and xanthan gum are blended, passedthrough a No. 10 mesh U.S. sieve, and then mixed with a previously madesolution of the microcrystalline cellulose and sodium carboxymethylcellulose in water. The sodium benzoate, flavor, and color are dilutedwith some of the water and added with stirring. Sufficient water is thenadded to produce the required volume.

FORMULATION EXAMPLE 8

Quantity Ingredient (mg/capsule) Active Ingredient  15.0 mg Starch 407.0mg Magnesium stearate  3.0 mg Total 425.0 mg

The active ingredient, starch, and magnesium stearate are blended,passed through a No. 20 mesh U.S. sieve, and filled into hard gelatincapsules in 425.0 mg quantities.

FORMULATION EXAMPLE 9

A subcutaneous formulation may be prepared as follows:

Ingredient Quantity Active Ingredient 5.0 mg Corn Oil 1.0 mL

FORMULATION EXAMPLE 10

A topical formulation may be prepared as follows:

Ingredient Quantity Active Ingredient 1-10 g Emulsifying Wax 30 g LiquidParaffin 20 g White Soft Paraffin to 100 g

The white soft paraffin is heated until molten. The liquid paraffin andemulsifying wax are incorporated and stirred until dissolved. The activeingredient is added and stirring is continued until dispersed. Themixture is then cooled until solid.

Another preferred formulation employed in the methods of the presentinvention employs transdermal delivery devices (“patches”). Suchtransdermal patches may be used to provide continuous or discontinuousinfusion of the compounds of the present invention in controlledamounts. The construction and use of transdermal patches for thedelivery of pharmaceutical agents is well known in the art. See, e.g.,U.S. Pat. No. 5,023,252, issued Jun. 11, 1991, herein incorporated byreference. Such patches may be constructed for continuous, pulsatile, oron demand delivery of pharmaceutical agents.

Frequently, it will be desirable or necessary to introduce thepharmaceutical composition to the brain, either directly or indirectly.Direct techniques usually involve placement of a drug delivery catheterinto the host's ventricular system to bypass the blood-brain barrier.One such implantable delivery system used for the transport ofbiological factors to specific anatomical regions of the body isdescribed in U.S. Pat. No. 5,011,472 which is herein incorporated byreference.

Indirect techniques, which are generally preferred, usually involveformulating the compositions to provide for drug latentiation by theconversion of hydrophilic drugs into lipid-soluble drugs. Latentiationis generally achieved through blocking of the hydroxy, carbonyl,sulfate, and primary amine groups present on the drug to render the drugmore lipid soluble and amenable to transportation across the blood-brainbarrier. Alternatively, the delivery of hydrophilic drugs may beenhanced by intra-arterial infusion of hypertonic solutions which cantransiently open the blood-brain barrier.

Other suitable formulations for use in the present invention can befound in Remington's Pharmaceutical Sciences, Mace Publishing Company,Philadelphia, Pa., 17th ed. (1985).

Utility

The compounds and pharmaceutical compositions of the invention areuseful in inhibiting β-amyloid peptize release and/or its synthesis,and, accordingly, have utility in treating Alzheimer's disease inmammals including humans.

As noted above, the compounds described herein are suitable for use in avariety of drug delivery systems described above. Additionally, in orderto enhance the in vivo serum half-life of the administered compound, thecompounds may be encapsulated, introduced into the lumen of liposomes,prepared as a colloid, or other conventional techniques may be employedwhich provide an extended serum half-life of the compounds. A variety ofmethods are available for preparing liposomes, as described in, e.g.,Szoka, et al., U.S. Pat. Nos. 4,235,871, 4,501,728 and 4,837,028 each ofwhich is incorporated herein by reference.

The amount of compound administered to the patient will vary dependingupon what is being administered, the purpose of the administration, suchas prophylaxis or therapy, the state of the patient, the manner ofadministration, and the like. In therapeutic applications, compositionsare administered to a patient already suffering from AD in an amountsufficient to at least partially arrest further onset of the symptoms ofthe disease and its complications. An amount adequate to accomplish thisis defined as “therapeutically effective dose.” Amounts effective forthis use will depend on the judgment of the attending cliniciandepending upon factors such as the degree or severity of AD in thepatient, the age, weight and general condition of the patient, and thelike. Preferably, for use as therapeutics, the compounds describedherein are administered at dosages ranging from about 0.1 to about 500mg/kg/day.

In prophylactic applications, compositions are administered to a patientat risk of developing AD (determined for example by genetic screening orfamilial trait) in an amount sufficient to inhibit the onset of symptomsof the disease. An amount adequate to accomplish this is defined as“prophylactically effective dose.” Amounts effective for this use willdepend on the judgment of the attending clinician depending upon factorssuch as the age, weight and general condition of the patient, and thelike. Preferably, for use as prophylactics, the compounds describedherein are administered at dosages ranging from about 0.1 to about 500mg/kg/day.

As noted above, the compounds administered to a patient are in the formof pharmaceutical compositions described above. These compositions maybe sterilized by conventional sterilization techniques, or may besterile filtered. When aqueous solutions are employed, these may bepackaged for use as is, or lyophilized, the lyophilized preparationbeing combined with a sterile aqueous carrier prior to administration.The pH of the compound preparations typically will be between 3 and 11,more preferably from 5 to 9 and most preferably from 7 and 8. It will beunderstood that use of certain of the foregoing excipients, carriers, orstabilizers will result in the formation of pharmaceutical salts.

The following synthetic and biological examples are offered toillustrate this invention and are not to be construed in any way aslimiting the scope of this invention. Unless otherwise stated, alltemperatures are in degrees Celsius.

EXAMPLES

In the examples below, the following abbreviations have the followingmeanings. If an abbreviation is not defined, it has its generallyaccepted meaning.

BOC=tert-butoxycabonyl

bd=broad doublet

bs=broad singlet

Cbz=carbobenzyloxy

cc=cubic centimeter

CDI=1,1′-carbonyldiimidazole

d=doublet

dd=doublet of doublets

DMF=dimethylformiamide

DMSO=dimethyl sulfoxide

EDC=1-(3-dimethyaminopropyl)-ethylcarbodiimide hydrochloride

EDTA=ethylene diamine tetraacetic acid

eq.=equivalents

ether=diethyl ether

g=grams

L=liter

m=multiplet

M=molar

max=maximum

mg=milligram

min.=minutes

mL=milliliter

mM=millimolar

mmol=millimole

N=normal

ng=nanogram

nm=nanometers

OD=optical density

pg=picograms

pM=picomolar

psi=pounds per square inch

q=quartet

quint.=quintet

rpm=rotations per minute

rt=room temperature

s=singlet

sept=septet

t=triplet

THF=tetrahydrofuran

tlc=thin layer chromatography

μg=microgram

μL=microliter

UV=ultraviolet

w/v=weight to volume

Additionally, the term “Aldrich” indicates that the compound or reagentused in the following procedures is commercially available from AldrichChemical Company, Inc., 1001 West Saint Paul Avenue, Milwaukee, Wis.53233 USA; the term “Bachem” indicates the compound or reagent iscommercially available from Bachem Biosciences Inc., 3700 Horizon Drive,Renaissance at Gulph Mills, King of Prussia, Pa. 19406 USA; the term“Fluka” indicates the compound or reagent is commercially available fromFluka Chemical Corp., 980 South 2nd Street, Ronkonkoma, N.Y. 11779 USA;the term “Lancaster” indicates the compound or reagent is commerciallyavailable from Lancaster Synthesis, Inc., P.O. Box 100, Windham, N.H.03087 USA; the term “Sigma” indicates the compound or reagent iscommercially available from Sigma, P.O. Box 14508, St. Louis, Mo. 63178USA; and the term “Sennchem” indicates the compound or reagent iscommercially available from Senn Chemicals AG, P.O. Box 267, CH-9157Dielsdorf, Switzerland.

In the examples below, all temperatures are in degrees Celsius (unlessotherwise indicated) and the following general procedures were usedprepare the compounds as indicated.

GENERAL PROCEDURE A Reductive Amination

To a solution of arylamine in ethanol in a hydrogenation flask was added1 equivalent of the 2-oxocarboxylic acid ester (e.g., pyruvate ester),followed by 10% palladium on carbon (25 weight percent based on thearylamine). The reaction was hydrogenated at 20 psi 2 on a Parr shakeruntil complete reaction was indicated by tic (30 minutes to 16 hours).The reaction mixture was then filtered through a pad of Celite 545(available from Aldrich Chemical Company, Inc.) and stripped free ofsolvent on a rotary evaporator. The crude product residue was thenfurther purified via chromatography.

GENERAL PROCEDURE B N-Heteroarylation of Alanine

A solution of 1.1 equivalents of L-alanine and 2 equivalents NaOH inDMSO was stirred at room temperature for 1 hour, then 1 equivalent of2-chlorobenzothiazole was added. The mixture was heated to 100° C. for 4hours, then cooled to room temperature and poured onto ice. The pH ofthe resulting aqueous solution was adjusted to ˜2, and the precipitatedsolid was removed by filtration. This solid was then dissolved in 1NNaOH and the resulting solution was filtered through a pad of Celite545. The pH of the filtrate was adjusted to ˜2, and the whiteprecipitate was removed by filtration and washed with water to yield theproduct.

GENERAL PROCEDURE C Ester Hydrolysis to Free Acid

Ester hydrolysis to the free acid was conducted by conventional methods.Below are two examples of such conventional de-esterification methods.

To a carboxylic ester compound (prepared, for example, by reductiveamination via General Procedure A to provide for the N-aryl amino acidester) in a 1:1 mixture of CH₃OH/H₂O was added 2-5 equivalents of K₂CO₃.The mixture was heated to 50° C. for 0.5 to 1.5 hours until tlc showedcomplete reaction. The reaction was cooled to room temperature and themethanol was removed on a rotary evaporator. The remaining aqueoussolution was adjusted to pH˜2, and ethyl acetate was added to extractthe product. The organic phase was then washed with saturated aqueousNaCl and dried over MgSO₄. The solution was stripped free of solvent ona rotary evaporator to yield the product.

The amino acid ester was dissolved in dioxane/water (4:1) to which wasadded LiOH (˜2 eq.) that was dissolved in water such that the totalsolvent after addition was about 2:1 dioxane:water. The reaction mixturewas stirred until reaction completion and the dioxane was removed underreduced pressure. The residue was diluted with EtOAc, the layers wereseparated and the aqueous layer acidified to pH 2. The aqueous layer wasback extracted with EtOAc, the combined organics were dried over Na₂SO₄and the solvent was removed under reduced pressure after filtration. Theresidue was purified by conventional methods (e.g., recrystallization).

The following exemplifies this latter example. The methyl ester of 3-NO₂phenylacetyl alanine 9.27 g (0.0348 mols) was dissolved in 60 mL dioxaneand 15 mL of H₂O and adding LiOH (3.06 g, 0.0731 mol) that has beendissolved in 15 mL of H₂O. After stirring for 4 hours, the dioxane wasremoved under reduced pressure and the residue diluted with EtOAc, thelayers were separated and the aqueous layer acidified to pH 2. Theaqueous layer was back extracted with EtOAc (4×100 mL), the combinedorganics were dried over Na₂SO₄ and the solvent was removed underreduced pressure after filtration. The residue was recrystallized fromEtOAc/isooctane giving 7.5 g (85%). C₁₁H₁₂N₂O₅ requires C, 52.38 H, 4.80N, 11.11. Anal found C, 52.54 H, 4.85 N, 11.08. [α]₂₃=−29.9 @ 589 nm.

GENERAL PROCEDURE D First EDC Coupling Procedure

To a 1:1 mixture of the desired acid and amino ester/amide in CH₂Cl₂ at0° C. was added 1.5 equivalents triethylamine, followed by 2.0equivalents hydroxybenzotriazole monohydrate, then 1.25 equivalents ofethyl-3-(3-dimethylamino)-propyl carbodiimide-HCl (EDC). The reactionwas stirred overnight at room temperature, then transferred to aseparatory funnel and washed with water, saturated aqueous NaHCO₃, 1NHCl, and saturated aqueous NaCl, and was then dried over MgSO₄. Thesolution was stripped free of solvent on a rotary evaporator to yieldthe crude product.

GENERAL PROCEDURE E Second EDC Coupling Procedure

The carboxylic acid was dissolved in methylene chloride. The amino acidester/amide (1 eq.), N-methylmorpholine (5 eq.) and hydroxybenzotriazolemonohydrate (1.2 eq.) were added in sequence. A cooling bath was appliedto the round bottomed flask until the solution reached 0° C. At thattime, 1.2 eq. of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimidehydrochloride (EDC) was added. The solution was allowed to stirovernight and come to room temperature under nitrogen pressure. Thereaction mixture was worked up by washing the organic phase withsaturated aqueous sodium carbonate, 0.1M citric acid, and brine beforedrying with sodium sulfate. The solvents were then removed to yieldcrude product. Pure products were obtained by flash chromatography in anappropriate solvent.

GENERAL PROCEDURE F BOC and tert-Butyl Ester Removal Procedure

The BOC- or tert-butyl ester compound was added to a 1:1 mixture ofCH₂Cl₂ and trifluoroacetic acid, and was stirred until tlc indicatedcomplete conversion, typically 2 hours. The solution was then strippedto dryness and the residue was taken up in ethyl acetate. For the BOCprotected compounds the solution was washed with dilute HCl. The aqueousphase was adjusted to a basic pH, then extracted with ethyl acetate. Forthe tert-butyl ester compounds, the solution was washed with saturatedaqueous NaHCO₃. The aqueous phase was then adjusted to pH 2 andextracted with ethyl acetate. The organic phase for either case was thenwashed with saturated aqueous NaCl and dried over MgSO₄. The solutionwas stripped free of solvent on a rotary evaporator to yield theproduct.

GENERAL PROCEDURE G N-Alkylation

To a solution of 3-aminoquinoline in CH₂Cl₂ was added 1.1 equivalent oftriethylamine, followed by a CH₂Cl₂ solution of p-nitrobenzenesulfonyl(nosyl) chloride. The reaction was stirred at room temperature for 5hours, then the di-nosylated aminoquinoline was isolated by filtrationand was washed with ethyl acetate. This material was then added to a 1:1mixture of dioxane and 1N NaOH and this solution was heated to 60° C.for 4 hours, at which time all solids had dissolved. The reaction wascooled to room temperature, then the pH was adjusted to ˜4. Theprecipitated mono-nosylated aminoquinoline was removed by filtration andwashed with H₂O. A solution of this compound in THF was then added to a−78° C. suspension of NaH in THF, then ethyl 2-bromopropionate wasadded. The reaction was warmed to rt, then refluxed for 4 days. Thecrude reaction mixture was stripped free of solvent on a rotaryevaporator, and the alkylated, nosylated aminoquinoline was obtained bychromatography. This product was then dissolved in DMF and 3 equivalentsK₂CO₃ was added, followed by 1.2 equivalents of thiophenol. The reactionwas stirred overnight at room temperature. The reaction was thenquenched with water and ether, and the organic phase was washed withsaturated aqueous NaHCO₃ and saturated aqueous NaCl, then dried overMgSO₄. The solution was stripped free of solvent on a rotary evaporatorto yield the crude product, which was then purified throughchromatography.

GENERAL PROCEDURE H Ester/Amide Exchange

To a solution of 3 equivalents of the desired amine in1,2-dichloroethane was added 5.2 equivalents trimethylaluminum whereinsaid addition was conducted below the surface of the solution viasyringe. After stirring for 30 minutes at room temperature, a solutionof the desired ester dissolved in 1,2-dichloroethane was added. Thereaction was refluxed until tlc showed complete conversion, typically 3hours. The reaction was then cooled to 0°C. and quenched with 10% HCl(Note: the acid should be added slowly as some foaming occurs during itsaddition). For those products not soluble in aqueous acid, the mixturewas transferred to a separatory funnel and the layers were separated.The aqueous phase was washed with ethyl acetate, and the organic phaseswere washed with saturated aqueous NaCl, dried over MgSO₄, andconcentrated under reduced pressure to leave the crude product.

For products soluble in aqueous acid, after reaction quench, thereaction volume was reduced to ˜1/3 of initial volume under reducedpressure. To the resulting solution was added 20% aqueous potassiumsodium tartrate (Rochelle's salt) and ethyl acetate. The pH of thesolution was adjusted to ˜13, and the aluminum salts dissolved in theaqueous solution. The organic phase was separated, and the aqueous phasewas extracted with ethyl acetate. The combined organic solution waswashed with saturated aqueous NaCl, dried over MgSO₄, and concentratedunder reduced pressure to leave the crude product.

GENERAL PROCEDURE I Ester Reduction to Alcohol

To a 0° C. solution of the starting ester in anhydrous THF was added 1.0equivalent of LiBH₄ in THF. The reaction was stirred at room temperatureovernight, and was then quenched with water. The THF was removed on arotary evaporator, and ethyl acetate was added, and the phases wereseparated. The organic phase was washed with saturated aqueous NaCl,dried over MgSO₄, and concentrated under reduced pressure to leave theproduct.

GENERAL PROCEDURE J Triflate Displacement

To a 0° C. solution of isobutyl R-(+)-lactate in CH₂Cl₂ was added 1.1equivalents of trifluoromethanesulfonic anhydride. After stirring atroom temperature for 20 minutes, 1.1 equivalents of 2,6-lutidine wasadded and stirring was continued for 10 min. This solution was thentransferred to a flask containing 1 equivalent arylamine and 1equivalent diisopropylethylanine in CH₂Cl₂ or CH₃NO₂ at 0° C. Thereaction was held overnight at room temperature, then stripped free ofsolvent on a rotary evaporator. The residue was dissolved in ethylacetate, washed with 5% citric acid, followed by saturated aqueous NaCl,and then the solution was stripped free of solvent on a rotaryevaporator to yield the crude product, which was then purified bychromatography.

GENERAL PROCEDURE K Methyl Ester Formation from Amino Acids

The amino acid (amino acid or amino acid hydrochloride) is suspended inmethanol and chilled to 0° C. HCl gas is bubbled through this solutionfor 5 min. The reaction is allowed to warrn to room temperature thenstirred for 4 hours. The solvents are then removed to afford the desiredamino acid methyl ester hydrochloride. This product is usually usedwithout further purification.

Example A Synthesis of N-(3,4-dichlorophenyl)-D,L-alanine

Using the procedure set forth in U.S. Pat. No. 3,598,859, the disclosureof which is incorporated herein by reference in its entirety,N-(3,4-dichlorophenyl)-D,L-alanine was prepared. Specifically, to asolution of 3,4-dichloroaniline (1 equivalent) (Aldrich) in isopropanol(about 500 mL per mole of 3,4-dichloroaniline) is added water (about0.06 mL per mL of isopropanol) and 2-chloropropionic acid (2equivalents) (Aldrich). This mixture is warmed to 40° C. and sodiumbicarbonate (0.25 equivalents) is added in successive portions beforeheating under reflux for 4-5 days. After cooling, the reaction mixtureis poured into water and the unreacted 3,4-dichloroaniline is removed byfiltration. The filtrate is acidified to pH 3-4 with concentratedhydrochloric acid and the resultant precipitate is filtered, washed anddried to yield the title compound, m.p.=148-149° C.

Alternatively, following Generad Procedure A above and using3,4-dichloroaniline (Aldrich) and ethyl pyruvate (Aldrich),N-(3,4-dichlorophenyl)-D,L-alanine ethyl ester was prepared as an oil.The reaction was monitored by tlc on silica gel (Rf=0.4 in 25%EtOAc/Hexanes) and purification was by preparative plate chromatography(silica gel using 25% EtOAc/Hexanes as eluent).

NMR data was as follows:

¹H-nmr (CDCl₃): δ=7.2 (d, 1H); 6.7 (d, 1H,); 6.4 (dd, 1H); 4.30 (bs,1H); 4.2 (q, 2H); 4.1 (q, 1H); 1.5 (d, 3H); 1.3 (t, 3H).

¹³C-nmr (CDCl₃): δ=175; 146.7; 133; 131; 121; 114.9; 112.6; 72.0; 52.4;28.3; 19.5.

C₁₁H₁₃Cl₂NO₂ (MW=262.14); mass spectroscopy (MH⁺) 263.

Hydrolysis of this ester via, e.g., General Procedure C provides thetitle compound.

Example B Synthesis of N-(3,5-dichlorophenyl)-D,L-alanine

Using the procedure set forth in U.S. Pat. No. 3,598,859 (or Example Aabove), N-(3,5-dichlorophenyl)-D,L-alanine was prepared using3,5-dichloroaniline (Aldrich) and 2-chloropropionic acid (Aldrich).

Example C Synthesis of N-(3,5-difluorophenyl)-D,L-alanine

Using the procedure set forth in U.S. Pat. No. 3,598,859 (or Example Aabove), N-(3,5-difluorophenyl)-D,L-alanine was prepared using3,5-difluoroaniline (Aldrich) and 2-chloropropionic acid (Aldrich).

Example D Synthesis of L-Valine N,N-dimethyl amide

To a stirred solution of 2.51 g (10 mmol) of Cbz-L-Valine (Bachem) in 20mL of DMF was added 1.46 g (9 mmol) of CDI and the mixture was stirredfor 50 min. To this mixture was added 6 mL (12 mmol) of dimethylamine(Aldrich) in 5 mL of THF and the reaction mixture was stirred for 18hours. The mixture was talken up in 100 mL of ethyl acetate, washed with10% HCl (3×40 mL), 10 mL of brine, and 20% potassium carbonate (2×50mL), and dried over MgSO₄. The mixture was, filtered and concentrated toyield Cbz-L-valine N,N-dimzthyl amide, which was hydrogenated understandard conditions with 10% Pd/C as the catalyst to remove the Cbzgroup and provide the title compound as an oil.

NMR data was as follows:

¹H-nmr (CDCl₃): δ=3.47 (d, J=5.4 Hz, 1H), 3.03 (s, 3H), 2.96 (s, 3H),1.83 (m, 1H), 1.60 (s, 2H), 0.95 (d, J=6.8 Hz, 3H), 0.89 (d, J=6.8 Hz,3H).

¹³C-nmr (CDCl₃): δ=175.1, 56.2, 37.0, 35.7, 32.0, 19.9, 16.8.

Example E Synthesis of L-Valine N-methyl amide

The title compound was prepared following the procedure described inExample D above and using methylamine in place of dimethylamine. Thetitle compound was an oil.

NMR data was as follows:

¹H-nmr (CDCl₃): δ=7.27 (bs, 1H), 3.20 (d, J=3.8 Hz, 1H), 2.79 (d, J=5.0Hz, 3H), 2.27 (m, 1H), 1.40 (bs, 2H), 0.96 (d, J=7.1 Hz, 3H), 0.79 (d,J=6.8 Hz, 3H).

¹³C-nmr (CDCl₃): δ=175.0, 60.1, 30.7, 25.6, 19.7, 15.9.

Example F Synthesis of BOC-Norleucine amide

To a stirred mixture of 3.47 g (15 mmol) of BOC-norleucine (Bachem),3.44 g (22.5 mmol) of 1-hydroxybenzotriazole monohydrate and 50 mL ofdichloromethane at 0° C. was added 3.45 g (1.2 mmol) of EDC. Theresulting mixture was stirred at 0° C. for 1 hour and then ammonia gaswas bubbled through the mixture for 10 min. The cooling bath was allowedto warm to room temperature and the mixture stirred for 18 hours. Themixture was evaporated to dryness, triturated with 20% Na₂CO₃. Theresulting solid was collected by filtration and washed wiith water toyield 2.69 g (11.7 mmol, 78%) of the title compound.

Example G Synthesis of N-[3,5-di(trifluoromethyl)phenyl]-L-alanine

Step A: Following General Procedure J and using3,5-di(trifluoromethyl)aniline (Aldrich) and isobutyl R-(+)-lactate(Aldrich), N-[3,5-di(trifluoromethyl)phenyl]-L-alanine isobutyl esterwas prepared as an oil. The reaction was monitored by silica gel tic(Rf=0.38 in 10% EtOAc/hexanes). Purification was by preparative platethin layer chromatography using 10% EtOAc/hexanes as the eluant.

NMR data was as follows:

¹H-nmr (CDCl₃): δ=7.13 (s, 1H), 6.91 (s, 2H), 4.97 (d, J=8.24 Hz, 1H),4.18 (m, 1H), 3.93 (d, J=6.59 Hz, 2H), 1.93 (sept, J=6.71 Hz, 1H), 1.49(d, J=7.02 Hz, 3H), 0.89 (d, J=6.59 Hz, 6H).

¹³C-nmr (CDCl₃): δ=174.4, 147.9, 133.6, 133.2, 132.7, 132.3, 129.4,125.8, 122.2, 118.6, 112.81, 112.76, 111.42, 111.37, 111.32, 111.27,111.22, 72.2, 52.0, 32.1, 28.24, 28.17, 23.2, 19.5, 19.3, 19.2, 18.9,14.6.

C₁₅H₁₇F₆NO₂ (MW=357.30); mass spectroscopy (MH⁺) 358.

Step B: N-[3,5-Di(trifluoromethyl)phenyl]-L-alanine isobutyl ester wasthen hydrolyzed according to General Procedure C using lithium hydroxidein THF.

Example H Synthesis of N-(3,5-dlimethoxyphenyl)-D,L-alanine

The title compound was prepared according to the procedure described inU.S. Pat. No. 3,598,859 (or Example A above) using 3,5-dimethoxyaniline(Aldrich) and 2-chloropropionic acid (Aldrich).

Example I Synthesis of N-(3,4-dichlorophenyl)glycine

Using the procedure set forth in U.S. Pat. No. 3,598,859,N-(3,4-dichlorophenyl)glycine was prepared using 3,4-dichloroaniline(Aldrich) and 2-chloroacetic acid (Aldrich).

Example J Synthesis of N-(3,5-dichlorophenyl)-D,L-phenylglycine

3,5-Dichloroaniline (1 eq.) (Aldrich) and methyl a-bromophenylacetate (1eq.) (Aldrich) were refluxed in ethanol with N-methyl morpholine(Aldrich) for 3 days. After standard work-up, the residue wascrystallized from ethyl acetate/hexane/ether/water to afford methylN-(3,5-dichlorophenyl)-D,L-phenylglycine. The methyl ester was thenhydrolyzed using 1M NaOH/water in methanol to afford the title compound.

Example 1 Synthesis of N-[N-(3,4-dichlorophenyl)-D,L-alanyl]-L-valinemethyl ester

Following General Procedure D (without the 1N HCl wash) and usingL-valine methyl ester hydrochloride (Sigma) andN-(3,4-dichlorophenyl)alanine (from Example A above), the title compoundwas prepared.

NMR data was as follows:

¹H-nmr (CDCl₃): δ=7.20 (m, 1H), 6.92-7.03 (m, 1H), 6.69 (m, 1H), 6.44(m, 1H), 4.50 (m, 1H), 4.19 (m, 1H), 3.78 (m, 1H), 3.71 (s, 1.5H), 3.65(s, 1.5H), 2.12 (m, 1H), 1.50 (d, J=7.0 Hz, 3H), 0.80-0.92 (m, 4.5H),0.71 (d, J=6.8 Hz, 1.5H).

³C-nmr (CDCl₃): δ=173.4, 173.0, 172.2, 171.8, 146.0, 145.8, 132.9,132.8, 130.7, 130.6, 121.7, 115.1, 114.8, 113.5, 113.1, 56.9, 56.6,55.1, 54.8, 52.2, 52.1, 31.1, 31.0, 30.9, 19.6, 19.4, 17.7, 17.4.

Example 2 Synthesis of N-[N-(3,4dichlorophenyl)-D,L-alanyl]-L-valineN-iso-butyl amide

Following General Procedure H above and usingN-[N-(3,4-dichlorophenyl)-D,L-alanyl]-L-valine methyl ester (fromExample 1 above) and isobutylamine (Aldrich), the title compound wasprepared as a oil. The reaction was monitored by tic (Rf=0.3 in 10%methanol/dichloromethane).

NMR data was as follows:

¹H-nmr (CDCl₃): δ=7.2 (d, 1H), 7.0 (m, 1H), 6.7 (m, 1H), 6.4 (m, 1H),4.6 (m, 1H), 4.1 (m, 1H), 3.8 (m, 3H), 3.6 (s, 3H), 1.9 (m, 2H), 1.4 (d,3H), 1.1 (m, 6H), 0.9 (m, 6H).

¹³C-nmr (CDCl₃): δ=173.8, 173.4, 172.9, 146.6, 133.6, 133.4, 131.3,122.5, 122.4, 115.8, 113.8, 56.9, 55.7, 38.2, 25.6, 20, 16, 12.1.

C₁₈H₂₇N₃O₂Cl₂ (MW=388.3); mass spectroscopy (MH⁺) 389.

Example 3 Synthesis of N-[N-(3,4dichlorophenyl)-D,L-alanyl]-L-threoninemethyl ester

Following General Procedure D (without the 1N HCl wash) and usingN-(3,4-dichlorophenyl)-D,L-alanine (from Example A above) andL-threonine methyl ester hydrochloride (Sigma), the title compound wasprepared as a oil. The reaction product was purified by silica gelchromatography using 50% ethyl acetate/hexane.

NMR data was as follows:

¹H-nmr (CDCl₃): δ=1.06 (d, J=6.4) and 1.17 (d, J=6.3; 3H total in 2:1ratio), 1.53 (d, J=7, 3H), 2.31 (d, J=5.6) and 2.58 (d, J=4.7; 1H totalin 2:1 ratio), 3.68 (s) and 3.75 (s) (3H total in 1:2 ratio), 3.8-3.9(m, 1H), 4.15-4.25 (m, 1H), 4.3-4.45 (m, 1H), 4.5-4.6 (m, 1H), 6.4-6.5(m, 1H), 6.65-6.7 (m, 1H), 7.4-7.55 (m, 2H).

¹³C-nmr (CDCl₃): δ=19.96, 20.23, 20.39, 20.49, 53.23, 53.28, 55.35,55.59, 57.5, 68.13, 68.21, 113.72, 1.14.20, 115.42, 115.60, 122.26,122.35, 131.22, 131.33, 133.41, 133.55, 146.417, 146.6, 171.63, 171.80,174.69, 174.86.

C₁₄H₁₈N₂O₄Cl₂ (MW=349.22); mass spectroscopy (MH⁺) 349.

Example 4 Synthesis of N-[N-(3,4dichlorophenyl)-D,L,alanyl]-L-valineethyl ester

Following General Procedure D (without the 1N HCl wash) and usingN-(3,4-dichlorophenyl)-D,L-alanine (from Example A above) and L-valineethyl ester HCl, the title compound was prepared as a oil The reactionproduct was purified by silica gel chromatography using 35% ethylacetate/hexane.

NMR data was as follows:

¹H-nmr (CDCl₃): δ=0.7-1.0 (overlapping group of d, J=7, 6H), 1.19 and1.27 (pair of t, J=7, 3H), 1.5 (d, J=7, 3H), 2.05-2.2 (m, 1H), 3.7-3.9(m, 1H), 4.0-4.3 (m, 3H), 4.5-4.6 (m, 1H), 6.4-6.5 (m, 1H), 6.5-6.6 (m,1H), 6.9-7.1 (M, 1H), 7.2-7.3 (M, 1H).

¹³C-nmr (CDCl₃): δ=14.65, 14.77, 17.96, 18.25, 19.56, 20.06, 20.31,31.77, 31.81, 55.50, 55.73, 57.22, 57.46, 61.88, 61.94, 113.76, 114.01,115.48, 115.76, 122.40, 122.46, 131.30, 131.33, 133.48, 133.61, 146.41,146.60, 171.86, 172.36, 173.54, 173.84.

C₁₆H₂₂N₂O₃Cl₂ (MW=361.27); mass spectroscopy (MH⁺) 361.

Example 5 Synthesis of N-[N-(3,4dichlorophenyl)-D,L-alanyl]-L-valinetert-butyl ester

Following General Procedure D (without the 1N HCl wash) and usingN-(3,4-dichlorophenyl)-D,L-alanine (from Example A above) and L-valinetert-butyl ester hydrochloride (Sigma), the title compound was preparedas a oil. The reaction product was purified by silica gel chromatographyusing 25% ethyl acetate/hexane.

NMR data was as follows:

¹H-nmr (CDCl₃): δ=0.7-1.0 (overlapping group of d, J=7, 6H), 1.36 (s)and 1.45 (s) (9H), 1.5-1.54 (2 d, J=7, 3H), 2.0-2.2 (m, 1H), 3.7-3.85(m, 1H), 4.1-4.2 (m, 1H), 4.3-4.5 (m, 1H), 6.4-6.5 (m, 1H), 6.7 (s, 1H),6.9-7.1 (m, 1H), 7.15-7.3 (m, 1H).

¹³C-nmr (CDCl₃): δ=17.84, 18.25, 19.50, 20.06, 20.29, 28.42, 28.62,31.96, 32.16, 55.45, 55.65, 57.53, 57.92, 82.72, 113.75, 114.00, 115.43,115.65, 122.26, 122.32, 1312-9, 131.50, 146.46, 146.65, 170.88, 171.48,173.39, 173.65.

C₁₈H₂₆N₂O₃Cl₂ (MW=389.33); mass spectroscopy (MH⁺) 389.

Example 6 Synthesis of N-[N-(3,4dichlorophenyl)-D,L-alanyl]-L-valineamide

Following General Procedure D (without the 1N HCl wash) and usingN-(3,4-dichlorophenyl)-D,L-alanine (from Example A above) and L-valineamide hydrochloride (Sigma), the title compound was prepared as a solidhaving a melting point of 156-158° C. The reaction product was purifiedby silica gel chromatography using 90:10:1 CH₂Cl₂:MeOH:NH₄OH.

NMR data was as follows:

¹H-nmr (DMSO-d₆): δ=0.6-0.9 (m, 6H), 1.2-1.4 (overlapping d, 3H),1.8-2.0 (m, 1H), 3.9-4.2 (m, 2H), 6.3-6.4 (m, 1H), 6.35-6.4 (m, 1H),6.7-6.8 (m, 1H), 7.0-7.15 (m, 1H), 7.2-7.3 (m, 1H), 7.4 (bs, 1H), 7.8(d, J=10) and 8.0 (d, J=10) (total 1H in 3:2 ratio).

¹³C-nmr (DMSO-d₆): δ=17.8, 18.2, 19.00, 19.25, 19.6, 19.7, 31.16, 31.20,51.9, 52.7, 57.11, 57.4, 113.46, 113.58, 113.67, 113.85, 117.20, 117.45,130.64, 130.76, 131.53, 131.56, 148.25, 148.45, 173.06, 173.11, 173.38,173.51.

C₁₄H₁₉N₃O₂Cl₂ (MW=331); mass spectroscopy (MH⁺) 332.

Example 7 Synthesis of N-(3,4-dichlorophenyl)-L-alanineN-(1-hydroxy-3-methyl-2-butyl) amide

Following General Procedure D (without the 1N HCl wash) and usingN-(3,4-dichlorophenyl)-D,L-alanine (from Example A above) and valinol(Sigma), the title compound was prepared as an oil. The reaction productwas purified by silica gel chromatography using 45:55 EtOAc/hexanes and90:10:1 CH₂Cl₂:MeOH:NH₄OH.

NMR data was as follows:

¹H-nmr (DMSO-d₆): δ=0.86 (d, J=7, 3H), 0.91 (d, J=7, 3H), 1.50 (d, J=7,3H), 1.8-2.0 (m, 1H), 2.6 (bs, 1H), 3.5-3.8 (m, 4H), 4.1 (bs, 1H), 6.45(dd, J=2.8, 8.7, 1H), 6.7 (d, J=2.8, 1H), 6.8 (bd, 1H), 7.2 (d, J =5,1H).

¹³C-nmr (DMSO-d₆): δ=19.3, 20.1, 20.2, 29.5, 55.8, 57.4, 64.1, 113.7,115.7, 122.4, 131.4, 133.5, 146.6, 174.6.

C₁₄H₂₀N₂O₂Cl₂ (MW=319.23); mass spectroscopy (MH⁺) 319.

Example 8 Synthesis of N-[N-(3,4-dichlorophenyl)-D,L-alanyl]-L-valineN,N-dimethyl amide

Following General Procedure D and using valine N,N-dimethyl amide (fromExample D above) and N-(3,4-dichlorophenyl)-D,L-alanine (from Example Aabove), the title compound was prepared as a solid (mp=145-160° C.).

NMR data was as follows:

¹H-nmr (CDCl₃): δ=7.38 (m, 1H), 7.14 (m, 1H), 6.66 (m, 1H), 6.41 (m,1H), 4.78 (m, 1H), 3.88 (m, 1H), 3.10 and 3.09 (s,s, 3H), 2.94 and 2.90(s,s, 3H), 1.96 (m, 1H), 1.43 (m 3H), 0.88 and 0.67 (m, 6H).

¹³C-nmr (CDCl₃): δ=173.6, 173.1, 171.4, 171.3, 146.3, 146.0, 132.7,132.6, 130.52, 130.46, 120.9, 120.8, 114.5, 113.4, 113.0, 54.25, 54.15,53.4, 53.2, 37.4, 35.6, 31.4, 31.3, 19.50, 19.46, 19.2, 17.5, 17.0.

C₁₆H₂₃N₃O₂Cl₂ (MW=360.29); mass spectroscopy (MH⁺) 360.

Example 9 Synthesis of N-[N-(3,4-dichlorophenyl)-D,L-alanyl]-valineN-methyl amide

Following General Procedure D and using L-valine N-methyl amide (fromExample E above) and N-(3,4-dichlorophenyl)-D,L-alanine (from Example Aabove), the title compound was prepared as a solid (mp=145-160° C.).

NMR data was as follows:

¹H-nmr (DMSO-d₆) δ=8.10 and 7.90 (m, 2H), 7.23 (m, 1H), 6.76 and 6.69(m, 1H), 6.57 (m, 1H), 6.34 (m, 1H), 3.90-4.14 (m, 2H), 2.57 and 2.56(s, s, 3H), 1.88 (m, 1H), 1.27 (m, 3H), 0.65-0.86 (m, 6H).

¹³ C-nmr (DMSO-d₆): δ=173.1, 171.2, 171.1, 148.1, 147.9, 131.19, 131.16,130.4, 130.2, 116.8, 113.5, 113.2, 113.1, 57.5, 57.3, 52.2, 51.5, 30.9,30.8, 25.4, 19.2, 19.1, 18.8, 18.6, 18.2, 17.9.

C₁₅H₂₁N₃O₂Cl₂ (MW=346.26); mass spectroscopy (MH⁺) 346.

Example 10 Synthesis of N-[N-(3,4-dichlorophenyl)-D,L-alanyl]-L-alaninemethyl ester

Following General Procedure D (without the 1N HCl wash) and usingL-alanine methyl ester hydrochloride (Sigma) andN-(3,4-dichlorophenyl)-D,L-alanine (from Example A above), the titlecompound was prepared as an oil. The reaction was monitored by tlc(Rf=0.24 in 1:1 EtOAc:Hexanes) and the product was purified by flashchromatography using 1:1 EtOAc:Hexanes as the eluent.

NMR data was as follows:

¹H-nmr (CDCl₃) δ=7.15 (m, 2H), 6.63 (dd, 1H), 6.40 (m, 1H), 4.50 (m,2H), 3.75 (m, 1H), 3.67 (s, 1.5H), 3.61 (s, 1.5H), 1.45 (d, 3H), 1.31(m, 3H).

¹³C-nmr (CDCl₃): δ=173.5, 173.2, 173.0, 172.8, 146.3, 146.2, 132.6,130.6, 130.5, 121.2, 114.9, 114.7, 113.3, 113.0, 54.6, 54.5, 52.43,52.39, 47.9, 47.8, 19.3, 19.1, 17.9, 17.8.

C₁₃H₁₆N₂O₃Cl₂ (MW=319.19); mass spectroscopy (MH⁺) 319.

Example 11 Synthesis of N-[N-(3,4dichlorophenyl)-L-alanyl]-L-leucinemethyl ester

Following General Procedure D and using L-leucine methyl esterhydrochloride (Sigma) and N-(3,4-dichlorophenyl)-D,L-alanine (fromExample A above), the title compound was prepared as a solid(mp=120-132° C.). The reaction was monitored by tlc (Rf=0.49 in 1:1EtOAc:Hexanes) and the product was purified by flash chromatographyusing 1:1 EtOAc:Hexanes as the eluent.

NMR data was as follows:

¹H-nmr (CDCl₃) δ=7.18 (d, 1H), 6.95 (bd, 1H), 6.69 (d, 1H), 6.43 (dd,1H), 4.58 (m, 1H), 4.32 (d, 1H), 3.75 (m, 1H), 3.61 (s, 3H), 1.54 (m,6H), 0.90 (m, 6H).

¹³C-nmr (CDCl₃): δ=174.1, 173.4, 146.8, 133.3, 131.2, 122.2, 115.7,114.1, 55.5, 52.9, 51.1, 41.6, 25.5, 23.4, 22.2, 20.0.

C₁₆H₂₂N₂O₃Cl₂ (MW=361.27); mass spectroscopy (MH⁺) 361.1.

Example 12 Synthesis ofN-[N-(3,4-dichlorophenyl)-L-alanyl]-L-phenylalanine methyl ester

Following General Procedure D and using L-phenylalanine methyl esterhydrochloride (Sigma) and N-(3,4-dichlorophenyl)-D,L-alanine (fromExample A above), the title compound was prepared as a solid(mp=122-124.5° C.). The reaction was monitored by tlc (Rf=0.47 in 1:1EtOAc:Hexanes) and the product was purified by flash chromatographyusing 1:1 EtOAc:Hexanes as the eluent.

NMR data was as follows:

¹H-nmr (CDCl₃) δ=7.21 (m, 4H), 7.05 (m, 2H), 6.91(d, 1H), 6.64 (d, 1H),6.38 (dd, 1H), 4.84 (q, 1H), 4.05 (bs, 1H), 3.71 (m, 4H), 3.20 (m, 1H),3.04 (m, 1H), 1.37 (d, 3H).

¹³C-nmr (CDCl₃): δ=173.6, 172.1, 146.5, 136.2, 133.4, 131.2, 129.7,129.1, 127.7, 122.3, 115.6, 113.9, 55.4, 53.3, 53.0, 38.1, 19.9.

C₁₉H₂₀N₂O₃Cl₂ (MW=395.29); mass spectroscopy (MH⁺) 395.

Example 13 Synthesis ofN-[N-(3,4dichlorophenyl)-D,L-alanyl]-L-isoleucine methyl ester

Following General Procedure D (without the 1N HCl wash) and usingL-isoleucine methyl ester hydrochloride (Sigma) andN-(3,4-dichlorophenyl)-D,L-alanine (from Example A above), the titlecompound was prepared as a solid (mp=95. 5-101.5° C.). The reaction wasmonitored by tlc (Rf=0.62 in 1:1 EtOAc:Hexanes) and the product waspurified by flash chromatography using 1:1 EtOAc:Hexanes as the eluent.

NMR data was as follows:

¹H-nmr (CDCl₃) δ=7.21 (d, 9H), 6.98 (m, 1H), 6.70 (m, 1H), 6.45 (m, 1H),4.55 (m, 1H), 4.11 (m, 1H), 3.79 (m, 1H), 3.72 (s, 1.5H), 3.67 (s,1.5H), 1.87 (m, 1H), 1.51 (d, 3H), 1.10 (m, 8H).

¹³C-nmr (CDCl₃): δ=173.8, 173.4, 172.9, 172.4, 146.6, 146.4, 133.6,133.4, 131.30, 131.28, 122.5, 122.4. 115.8, 115.4, 114.1, 113.8, 56.9,56.8, 55.7, 55.5, 52.8, 52.7, 38.3, 38.2, 25.6, 25.5, 20.2, 20.0, 16.05,16.03, 12.1, 12.0.

C₁₆H₂₂N₂O₃Cl₂ (MW=361.27); mass spectroscopy (MH⁺) 361.1.

Example 14 Synthesis ofN-N[-(3,4-dichlorophenyl)-L-alanyl]-(S)-2-aminopentanoic acid methylester

Following General Procedure D (without the 1N HCl wash) and usingL-norvaline methyl ester hydrochloride (Sennchem) andN-(3,4-dichlorophenyl)-D,L-alanine (from Example A above), the titlecompound was prepared as a solid (mp=150-153° C.). The reaction wasmonitored by tic (Rf=0.57 in 1:1 EtOAc:Hexanes) and the product waspurified by flash chromatography using 1:1 EtOAc:Hexanes as the eluant.

NMR data was as follows:

¹H-nmr (CDCl₃) δ=7.21 (d, 1H), 6.95 (bd, 1H), 6.70 (d, 1H), 6.47 (dd,1H), 4.57 (m, 1H), 4.13 (bd, 1H), 3.78 (m, 1H), 3.67 (s, 3H), 1.81 (m,1H), 1.62 (m, 1H), 1.51 (d, 3H), 1.30 (m, 2H), 0.9 (t, 3H).

¹³C-nmr (CDCl₃): δ=173.8, 173.0, 146.6, 133.4, 131.3, 122.4, 115.7,114.1, 55.6, 52.9, 52.4, 34.8, 20.2, 19.2, 14.2.

C₁₅H₂₀N₂O₃Cl₂ (MW=347.24); mass spectroscopy (MH⁺) 347.

Example 15 Synthesis ofN-[N-(3,4dichlorophenyl)-L-alanyl]-(S)-2-aminohexanoic acid methyl ester

Following General Procedure D (without the 1N HCl wash) and usingL-norleucine methyl ester hydrochloride (Sigma) andN-(3,4-dichlorophenyl)alanine (from Example A above), the title compoundwas prepared as a solid (mp=163-165° C.). The reaction was monitored bytlc (Rf=0.55 in 1:1 EtOAc:Hexanes) and the product was purified by flashchromatography using 1:1 EtOAc:Hexanes as the eluent.

NMR data was as follows:

¹H-nmr (CDCl₃) δ=7.18 (d, 1H, J=8.7 Hz), 6.99 (bd, 1H, J=8.2 Hz), 6.69(d, 1H, J=2.7 Hz), 6.45 (dd, 1H, J=8.7 Hz, J=2.7 Hz), 4.53 (m, 1H), 4.23(d, 1H, J=4.2 Hz), 3.77 (m, 1H), 3.66 (s, 3H), 1.83 (m, 1H), 1.62 (m,1H), 1.48 (d, 3H, J=7.0 Hz), 1.27 (m, 4H), 0.85 (t, 3H).

¹³C-nmr (CDCl₃): δ=173.9, 173.1, 146.7, 133.4, 131.2, 122.3, 115.7,114.1, 55.5, 52.9, 52.6, 32.4, 28.0, 22.8, 20.1, 14.4.

C₁₆H₂₂N₂O₃Cl₂ (MW=361.27); mass spectroscopy (MH⁺) 361.

Example 16 Synthesis ofN-[N-(3,4dichlorophenyl)-D,L-alanyl]-L-tryptophan methyl ester

Following General Procedure D (without the 1N HCl wash) and usingL-tryptophan methyl ester hydrochloride (Sigma) andN-(3,4-dichlorophenyl)-D,L-alanine (from Example A above), the titlecompound was prepared as a solid (mp=54-66° C.). The reaction wasmonitored by tlc (Rf=0.43 in 1:1 EtOAc:Hexanes) and the product waspurified by flash chromatography using 1:1 EtOAc:Hexanes as the eluent.

NMR data was as follows:

¹H-nmr (CDCl₃) δ=8.15 (bs, 0.5H), 7.98 (bs, 0.5H), 7.51 (d, 0.5H), 7.12(m, 6H), 6.60 (d, 0.5H), 6.53 (dd, 1H), 6.24 (m, 1H), 4.88 (m, 1H), 3.90(d, 0.5H), 3.70 (m, 4.5H), 3.32 (m, 1H), 3.22 (m, 1H), 1.40 (m, 3H).

¹³C-nmr (CDCl₃): δ=173.8, 173.6, 172.8, 172.4, 146.4, 146.3, 136.6,133.3, 133.2, 131.2, 131.1, 128.2, 127.7, 123.3, 122.8, 122.05, 122.02,120.3, 120.2, 119.0, 118.7, 115.5, 115.4, 113.8, 113.3, 112.1, 111.9,110.2, 109.9, 55.3, 55.1, 53.5, 53.1, 53.0, 52.9, 27.9, 27.7, 19.8,19.6.

C₂₁H₂₁N₃O₃Cl₂ (MW=434.33); mass spectroscopy (MH⁺) 434.

Example 17 Synthesis of N-[N-(3,4-dichlorophenyl)-D,L-alanyl]-L-asparticacid β-(tert-butyl ester) α-methyl ester

Following General Procedure D (without the 1N HCl wash) and usingL-aspartic acid β-(tert-butyl ester) α-methyl ester hydrochloride(Bachem) and N-(3,4-dichlorophenyl)-D,L-alanine (from Example A above),the title compound was prepared. The reaction was monitored by tlc(Rf=0.56 in 1:1 EtOAc:Hexanes) and the product was purified by flashchromatography using 1:1 EtOAc:Hexanes as the eluent.

NMR data was as follows:

¹H-nmr (CDCl₃) δ=7.52 (d, 0.5H), 7.42 (d, 0.5H), 7.13 (m, 1H), 6.66 (d,0.5H), 6.60 (d, 0.5H), 6.40 (m, 1H), 4.76 (m, 1H), 4.40 (d, 0.5H), 4.31(d, 0.5H), 3.75 (m, 1H), 3.69 (s, 1.5H), 3.62 (s, 1.5H), 2.88 (m, 1H),2.62 (m, 1H), 1.47 (m, 3H), 1.32 (s, 4.5H), 1.21 (s, 4.5H).

¹³C-nmr (CDCl₃): δ=174.0, 173.7, 171.7, 171.4, 170.30, 170.27, 146.7,146.6, 133.4, 133.3, 131.2, 131.1, 122.0, 115.6, 115.1, 114.0, 113.4,82.4, 55.4, 55.2, 53.24, 53.19, 49.0, 48.7, 37.9, 37.8, 28.4, 28.2,19.9, 19.8.

C₁₈H₂₄N₂O₅Cl₂ (MW=419.31); mass spectroscopy (MH⁺) 418.

Example 18 Synthesis of N-[N-(3,4dichlorophenyl)-D,L-alanyl]-L-asparticacid methyl ester

The tert-butyl ester group ofN-[N-(3,4-dichlorophenyl)-D,L-alanyl]-L-aspartic acid β-(tert-butylester) α-methyl ester (from Example 17 above) was removed via GeneralProcedure F to provide for the title compound as a solid (mp=53.5-56°C.). The reaction was monitored by tlc (Rf=0.54 in 1:1 EtOAc:Hexanes).

NMR data was as follows:

¹H-nmr (CDCl₃) δ=7.59 (d, 1H), 7.18 (m, 1H), 6.79 (d, 0.5 H), 6.69 (d,0.5H), 6.58 (m, 0.5H), 6.47 (m, 0.5H), 4.84 (m, 1H), 3.82 (m, 1H), 3.73(s, 1.5H), 3.68 (s, 1.5H), 3.04 (m, 1H), 2.79 (m, 0.5H), 2.73 (m, 0.5H),1.49 (m, 3H).

¹³C-nmr (CDCl₃): δ=175.7, 175.6, 175.14, 175.07, 171.1, 171.0, 145.0,144.6, 133.6, 133.5, 131.44, 131.40, 124.2, 123.4, 55.9, 55.4, 53.8,53.7, 49.05, 49.00, 36.1, 19.2, 19.1.

C₁₄H₁₆N₂O₅Cl₂ (MW=363.20); mass spectroscopy (MH⁺) 363.

Example 19 Synthesis ofN-[N-(3,4dichlorophenyl)-D,L-alanyl]-Nε-BOC-L-lysine methyl ester

Following General Procedure D and usingN-(3,4-dichlorophenyl)-D,L-alanine (from Example A above) andNε-BOC-L-lysine methyl ester hydrochloride (Bachem), the title compoundwas prepared as a oil. The reaction was monitored by tlc (Rf=0.23 in 45%ethyl acetate/hexanes).

NMR data was as follows:

¹H-nmr (CDCl₃): δ=7.22 (m, 4H), 6.63 (q, 1H), 6.43 (m, 1H), 4.72 (t,0.5H), 4.63 (t, 0.5H), 4.53 (m, 1H), 4.42 (q, 1H), 3.78 (m, 1H), 3.68(s, 1.5H), 3.62 (d, 1.5H), 3.00 (m, 2H), 1.90-1.05 (m, 4H), 1.48 (d,3H), 1.42 (s, 9H).

¹³C-nmr (CDCl₃): δ=174.2, 173.9, 173.1, 172.8, 156.7, 156.6, 146.8,146.7, 133.4, 133.3, 131.2, 131.1, 121.9, 121.8, 115.5, 115.1, 114.0,113.8, 79.7, 79.6, 60.9, 55.2, 55.1, 53.0, 52.9, 52.4, 52.1, 40.6, 40.5,32.3, 32.2, 30.1, 28.9, 22.8, 21.6, 19.9, 14.7.

Example 20 Synthesis ofN-[N-benzothiazol-6yl)-D,L-alanyl]-(S)-2-amninohexanoic acid methylester

Step A: Synthesis of N-[N-benzothiazol-6yl)-D,L-alanine

A solution of 1 gram of 6-aminobenzothiazole (Lancaster) in 60 mL ofdichloromethane was treated with 0.63 grams of pyridine and then 2.1grams of trifluoroacetic acid anhydride at room temperature. Thereaction was stirred for 3 hours during which time the initially warmreaction mixture cooled to room temperature. The mixture was washed witha 5% aqueous citric acid solution, dried with MgSO₄ and the solventsremoved to provide a quantitative yield of 6-aminobenzotriazoletrifluoroacetamide as a cream colored solid that was used immediately inthe following reaction.

A 300 mg portion of 6-aminobenzotriazole trifluoroacetamide wasdissolved in 35 mL of THF and added to 1.2 eq. of KH at roomtemperature. The solution was refluxed for 5 hours, cooled and a crystalof 18-crown-6 (Aldrich) was added along with 331 mg of ethyl2-bromopropionate (Aldrich) and the resulting mixture was refluxed for36 hours. The reaction mixture was cooled, the solvents removed underreduced pressure and the residue dissolved in ethyl acetate. Theorganics were washed with water. The aqueous layer pH was adjusted to pH5 and extracted with ethyl acetate. The organics were combined, driedwith MgSO₄ and the solvents removed. The crude material was purified bypreparative tlc using dichloromethane/methanol (94:4) to giveN-(benzothiazol-6-yl)-D,L-alanine ethyl ester (Rf=0.5). This materialwas treated with methanol and 5 eq. of potassium carbonate at reflux,and then cooled and the solvents removed. The residue was taken up inwater and ethyl acetate. The aqueous layer was adjusted to pH 2 andextracted with ethyl acetate. The ethyl acetate extracts were dried andthe solvents removed to provide N-(benzothiazol-6-yl)-D,L-alanine.

Step B: Synthesis ofN-[N-benzothiazol-6yl)-D,L-alanyl]-(S)-2-aminohexanoic acid methyl ester

Following General Procedure D (using DMF as the reaction solvent, ethylacetate for extraction and without the 1N HCl wash) and usingL-norleucine methyl ester hydrochloride (Sigma) andN-(benzothiazol-6-yl)-D,L-alanine (from Step A above), the titlecompound was prepared. The reaction was monitored by tlc (Rf=0.28 in 1:1EtOAc:Hexanes) and the product was purified by flash chromatographyusing 1:1 EtOAc:Hexanes as the eluent.

NMR data was as follows:

¹H-nmr (CDCl₃) δ=8.74 (s, 1H), 7.91 (s, 1H, J=8.8 Hz), 7.15 (m, 1H),7.06 (d, 0.5H, J=2.3 Hz), 7.00 (d, 0.5H, J=2.3 Hz), 6.87 (m, 1H), 4.58(m, 1H), 4.20 (bs, 2H), 3.87 (m, 1H), 3.70 (s, 1.5H), 3.59 (s, 1.5H),1.30 (m, 10H), 0.84 (t, 1.5H, J=6.9 Hz), 0.60 (t, 1.5H, J=6.9H).

¹³C-nmr (CDCl₃): δ=174.3, 174.0, 173.4, 173.0, 151.1, 151.0, 147.2,145.5, 145.3, 136.2, 136.1, 124.4, 124.2, 116.1, 115.9, 104.6, 103.9,56.2, 55.69, 53.0, 52.9, 52.5, 52.2, 32.42, 32.36, 28.0, 27.7, 22.8,22.6, 20.3, 20.1, 14.4, 14.2.

C₁₇H₂₃N₃O₃S2 (MW=349.46); mass spectroscopy (MH⁺) 350.

Example 21 Synthesis of N-[N-(3,4-dichlorophenyl)-D,L-alanyl]-L-lysinemethyl ester

Following General Procedure F and usingN-[N-(3,4-dichlorophenyl)-D,L-alanyl]-Nε-BOC-L-lysine methyl ester (fromExample 19 above), the title compound was prepared as an oil. Thereaction product was purified by silica gel chromatography using 89:10:1CH₂Cl₂:MeOH:NH₄OH.

NMR data was as follows:

¹H-nmr (CDCl₃-2 diastereomers): δ=7.21 (d, 1H), 7.09 (bd, 1H), 6.68 (q,1H), 6.46 (m, 1H), 4.56 (m, 1H), 4.22 (bs, 1H), 3.78 (m, 1H), 3.70 (s,1.5H), 3.67 (s, 1.5H), 2.66 (t, 1H), 2.54 (t, 1H), 1.80 (m, 1H), 1.62(m, 1H), 1.51 (d, 1.5H), 1.50 (d, 1.5H), 1.32 (m, 2H), 1.11 (m, 1H).

¹³C-nmr (CDCl₃-2 diastereomers): δ=174.8, 174.3, 173.1, 172.8, 171.8,146.9, 146.7, 133.3, 133.1, 131.2, 131.1, 121.7, 121.5, 115.2, 115.1,113.9, 113.8, 60.9, 55.0, 54.9, 53.1, 53.0, 52.5, 52.3, 32.1, 32.09,32.05, 31.8, 23.1, 22.9, 21.6, 19.9, 19.8, and 14.7.

C₁₆H₂₃N₃O₃Cl₂ (MW=376.28).

Example 22 Synthesis of N-[N-(3,4-dichlorophenyl)-D,L-alanyl]-L-tyrosinemethyl ester

Following General Procedure D and using L-tyrosine methyl ester (Sigma)and N-(3,4-dichlorophenyl)-D,L-alanine (from Example A above), the titlecompound was prepared as a mixture of stereoisomers about alanine. Thereaction was monitored by tlc (Rf=0.29 in 10% MeOH/CH₂Cl₂) andpurification was by flash chromatography (10% methanol/methylenechloride).

NMR data was as follows:

¹H-nmr (CDCl₃) δ=7.22-7.50 (m, 7H), 6.36 (dd, 0.5H), 6.28 (dd, 0.5H),4.83 (m 1H), 4.04 (dd, 1H), 3.73 (s, 1.5H), 3.70 (m, 1H), 3.68 (s,1.5H), 3.14 (dd, 0.5H), 2.97 (m, 1.5H), 1.43 (d, 1.5H), 1.35 (d, 1.5H).

¹³C-nmr (CDCl₃): δ=174.20, 174.08, 172.75, 172.26, 156.10, 155.99,146.45, 146.32, 133.50, 133.38, 131.39, 131.26, 130.81, 130.67, 127.43,127.00, 122.41, 122.22, 116.15, 116.12, 115.68, 115.39, 113.94, 113.46,55.47, 55.08, 53.54, 53.18, 37.62, 37.44, 19.91, 19.87.

C₁₉H₂₀N₂O₄Cl₂ (MW=411.28).

Example 23 Synthesis of N-[N-(3,5-dichlorophenyl)-D,L-alanyl]-L-alaninemethyl ester

Following General Procedure D and usingN-(3,5-dichlorophenyl)-D,L-alanine (from Example B above) and L-alaninemethyl ester hydrochloride (Sigma), the title compound was prepared as aoil. The reaction product was purified by silica gel chromatographyusing 50% ethyl acetateihexane.

NMR data was as follows:

¹H-nmr (CDCl₃): δ=1.3-1.55 (three sets of doublets at 1.34, 1.39 and1.48, all J=7, total 6H), 3.7-3.9 (m with singlets at 3.67 and 3.72,4H), 4.3-4.4 (m, 1H) 4.5-4.65 (m, 1H), 6.4-6.6 (m, 2H), 6.73 (s, 1H),6.95-7.1 (m, 1H).

¹³C-nmr (CDCl₃): δ=15.52, 15.59, 16.75, 16.87, 45.29, 45.39, 50.02,51.89, 51.99, 108.9, 109.2, 109.5, 116.14, 116.19, 132.96, 133.96,133.05, 145.67, 145.76, 170.13, 170.32, 170.40, 170.63.

C₁₃H₁₆N₂O₃Cl₂ (MW=319.19); mass spectroscopy (MH⁺) 319.

Example 24 Synthesis ofN-[N-(3,5-dichlorophenyl)-L-alanyl]-(S)-2-aminopentanoic acid methylester

Following General Procedure D and usingN-(3,5-dichlorophenyl)-D,L-alanine (from Example B above) andL-norvaline methyl ester hydrochloride (Sennchem), the title compoundwas prepared. The reaction product was purified by silica gelchromatography using 50% ethyl acetate/hexane.

NMR data was as follows:

¹H-nmr (CDCl₃): δ=0.92 (t, J=7, 3H), 1.2-1.4 (m, 2H), 1.50 (d, J=7, 3H),1.5-1.7 (m, 1H), 1.75-1.9 (m, 1H), 3.69 (s, 3H), 3.75-3.9 (m, 1H), 4.2(bs, 1H), 4.5-4.65 (m, 1H), 6.5 (bs, 2H), 6.73 (s, 1H), 6.85 (bs, 1 H).

¹³C-nmr (CDCl₃): δ=14.2, 19.25, 20.13, 34.8, 52.4, 53.0, 55.2, 112.7,119.5, 136.1, 148.7, 173.0, 173.5.

C₁₅H₂₀N₂O₃Cl₂ (MW=347.24); mass spectroscopy (MH⁺) 346.

Example 25 Synthesis ofN-[N-(3,5-dichlorophenyl)-L-alanyl]-L-phenylalanine methyl ester

Following General Procedure D and usingN-(3,5-dichlorophenyl)-D,L-alanine and L-phenylalanine methyl esterhydrochloride (Sigma), the title compound was prepared. The reactionproduct was purified by silica gel chromatography using 50% ethylacetate/hexane.

NMR data was as follows:

¹H-nmr (CDCl₃): δ=1.40 (d, J=7, 3H), 3.10 (dd, J=7,14, 1H), 3.23 (dd,J=5,14, 1H), 3.74 (s, 3H), 3.75-3.9 (m, 1H), 4.0 (bs, 1H), 4.8-4.95 (m,1H), 6.45 (bs, 2H), 6.73 (s, 2H), 7.0-7.2 (m, 2H), 7.2-7.3 (m, 5H).

¹³C-nmr (CDCl₃): δ=19.4, 37.5, 52.4, 52.7, 54.5, 112.0, 118.9, 127.1,128.5, 129.1, 135.5, 135.6, 148.0, 171.4, 172.6.

C₁₉H₂₀N₂O₃Cl₂ (MW=395.29); mass spectroscopy (MH⁺) 394.

Example 26 Synthesis of N-[N-(3,4dichlorophenyl)-D,L,alanyl]-L-asparticacid β-(methyl ester) α-methyl ester

Following General Procedure D (without the 1N HCl wash) and usingL-aspartic acid β-(methyl ester) α-methyl ester (Sigma) andN-(3,4-dichlorophenyl)-D,L-alanine (from Example A above), the titlecompound was prepared as a solid (mp=113.5-118° C.). The reaction wasmonitored by tlc (Rf=0.29 in 1:1 EtOAc:Hexanes) and the product waspurified by flash chromatography using 1:1 EtOAc:Hexanes as the eluent.

NMR data was as follows:

¹H-nmr (CDCl₃) δ=7.47 (bd, 1H), 7.20 (m, 1H), 6.69 (d, 0.5H), 6.60 (d,0.5H), 6.44 (m, 1H), 4.83 (m, 1H), 4.25 (bs, 0.5H), 4.18 (bs, 0.5H),3.79 (m, 1H), 3.72 (s, 1.5H), 3.67 (s, 1.5H), 3.65 (s, 1.5H), 3.48 (s,1.5H), 3.00 (m, 1H), 2.79 (m, 1H), 1.50 (m, 3H).

¹³C-nmr (CDCl₃): δ=174.0, 173.6, 172.0, 171.7, 171.4, 171.3, 146.6,146.4, 133.43, 133.37, 131.22, 131.20, 122.2, 122.0, 115.5, 115.0,114.1, 113.6, 55.4, 55.2, 53.46, 53.44, 52.7, 52.5, 48.8, 48.7, 36.4,36.3, 19.9, 19.7.

C₁₅H₁₈N₂O₅Cl₂ (MW=377.23); mass spectroscopy MH⁺) 377.

Example 27 Synthesis ofN-[N-(3,4dichlorophenyl)-D,L-alanyl]-(N′-1-benzyl)-L-histidine methylester

Following General Procedure D (without the 1N HCl wash) and using1-benzyl-L-histidine methyl ester hydrochloride (Sigma) andN-(3,4-dichlorophenyl)-D,L-alanine (from Example A above), the titlecompound was prepared as a solid (mp=49-51° C.). The reaction wasmonitored by tlc (Rf=0.21 in 5% methanol/methylene chloride) and theproduct was purified by flash chromatography using 5% methanol:methylene chloride as the eluent.

NMR data was as follows:

¹H-nmr (CDCl₃) δ=8.22 (d, 0.5H), 7.88 (d, 0.5H), 7.29 (m, 3H), 7.08 (m,4H), 6.65 (d, 0.5H), 6.44 (m, 2.5H), 4.90 (s, 1H), 4.86 (s, 1H), 4.62(m, 1H), 4.47 (m, 1H), 3.72 (m, 1H), 3.61 (s, 1.5H), 3.47 (s, 1.5H),2.95 (m, 2H), 1.42 (d, 3H).

¹³C-nmr (CDCl₃): δ=174.0, 173.9, 172.4, 172.0, 146.9, 138.1, 137.9,137.6, 136.7, 136.5, 133.1, 133.0, 131.0, 130.9, 129.6, 129.5, 128.84,128.79, 127.74, 127.71, 121.1, 121.0, 117.3, 115.3, 115.1, 113.9, 113.6,54.9, 54.8, 53.2, 52.9, 52.8, 52.7, 51.3, 51.2, 30.2, 29.8, 19.8.

C₂₃H₂₄N₄O₃Cl₂ (MW=475.38); mass spectroscopy (MH⁺) 475.

Example 28 Synthesis of N-[N-(3,4-dichlorophenyl)-D,L-alanyl]-L-glutamicacid β-(tert-butyl ester) α-methyl ester

Following General Procedure D (without the 1N HCl wash) and usingL-glutamic acid β-(tert-butyl ester) α-methyl ester hydrochloride(Bachem) and N-(3,4-dichlorophenyl)-D,L-alanine (from Example A above),the title compound was prepared as an oil. The reaction was monitored bytic (Rf=0.52 and 0.59 in 1:1 EtOAc:Hexanes) and the product was purifiedby flash chromatography using 1:1 EtOAc:Hexanes as the eluent.

NMR data was as follows:

¹H-nmr (CDCl₃) δ=7.25 (m, 2H), 6.69 (m, 1H), 6.45 (m, 1H), 4.54 (m, 1H),3.78 (m, 1H), 3.70 (s, 1.5H), 3.65 (s, 1.5H), 2.10 (m, 4H), 1.49 (d,3H), 1.40 (s, 9H).

¹³C-nmr (CDCl₃): δ=174.2, 173.9, 172.8, 172.7, 172.5, 172.3, 146.6,146.5, 133.5, 133.3, 131.3, 131.2, 122.16, 122.14, 115.7, 115.4, 114.0,113.6, 81.6, 81.5, 55.4, 55.2, 53.1, 53.0, 52.3, 51.9, 32.0, 31.7, 28.6,27.6, 27.3, 20.0, 19.8.

C₁₉H₂₆N₂O₅Cl₂ (MW=433.34); mass spectroscopy (MH⁺) 432.

Example 29 Synthesis of N-[N-(3,4-dichlorophenyl)-D,L,alanyl]-L-glutamicacid α-methyl ester

The tert-butyl ester group of N-[N-(3,4-dichlorophenyl)alanyl]glutamicacid β-(tert-butyl ester) α-methyl ester (from Example 28 above) wasremoved via General Procedure F (the NaHCO₃ wash was omitted and theproduct was recovered from the ethyl acetate phase) to provide for thetitle compound as a solid (mp=42-45° C.). The reaction was monitored bytlc (Rf=0.42 and 0.50 in 10% methanol/methylene chloride).

NMR data was as follows:

¹H-nmr (CDCl₃) δ=7.57 (bs, 1H), 7.25 (d, 1H), 6.75 (d, 1H), 6.51 (m,1H), 4.67 (m, 1H), 3.91 (m, 1H), 3.76 (s, 1.5H), 3.69 (s, 1.5H),2.50-2.15 (m, 3H), 2.10-1.85 (m, 1H), 1.51 (bs, 3H).

¹³C-nmr (CDCl₃): δ=177.98, 177.73, 175.17, 174.94, 172.64, 172.26,146.60 ,146.45, 133.52, 133.33, 131.41, 131.27, 122.32, 122.28, 115.68,155.47, 113.98, 113.59, 55.37, 55.17, 53.35, 53.29, 52.20, 51.85, 30.68,30.26, 227.29, 27.18, 19.86, 19.77.

C₁₅H₁₈N₂O₅Cl₂ (MW=377.2.3).

Example 30 Synthesis of N-[N-(3,4-dichlorophenyl)-L-alanyl]-L-leucineamide

Following General Procedure D and using L-leucinamide hydrochloride(Sigma) and N-(3,4-dichlorophenyl)-D,L-alanine (from Example A above),the title compound was prepared. This compound was then purified bycolumn chromatography, eluted first with 1:1 EtOAc/hexane, then with 5%MeOH in methylene chloride.

NMR data was as follows:

¹H-nmr (CDCl₃) δ=7.32 (d, 8.6, 1H), 7.17 (d, 8.7, 1H), 6.66 (d, 2.7,1H), 6.54 (s, 1H), 6.41 (dd, 2.7, 8.7, 1H), 6.13 (s, 1H), 4.48 (m, 1H),4.33 (d, 5.3, 1H), 3.83 (quint, 6.9, 1H), 1.58 (m, 3H), 1.44 (d, 7.0,3H), 0.89 (d, 6.0, 3H), 0.85 (d, 5.9, 3H).

¹³C-nmr (CDCl₃): δ=174.5, 173.9, 146.0, 132.8, 130.7, 121.5, 114.7,113.3, 54.3, 51.1, 40.8, 24.8, 22.9, 21.7, 19.2.

C₁₅H₂₁N₃O₂Cl₂ (MW=346.26); mass spectroscopy (MH⁺) 346.

Example 31 Synthesis ofN-[N-(3,4dichlorophenyl)-D,L-alanyl]-(3,5-diiodo)-L-tyrosine methylester

Following General Procedure D and using 3,5-diiodo-L-tyrosine methylester hydrochloride (Bachem) and N-(3,4-dichlorophenyl)-D,L-alanine(from Example A above), the title compound was prepared as a mixture ofstereoisomers about alanine. The reaction was monitored by tic (Rf=0.29in 10% MeOH/CH₂Cl₂) and purification was by flash chromatography (10%methanol/methylene chloride).

NMR data was as follows:

¹H-nmr (CDCl₃—partially pure diastereomer A) δ=7.37 (s, 2H), 7.19 (d,1H), 6.99 (bd, 1H), 6.65 (d, 1H), 6.40 (m, 1H), 5.78 (s, 1H), 4.73 (q,1H), 3.72 (m, 1H), 0.70 (s, 3H).

¹³C-nmr (CDCl₃—two diastereomers): δ=173.86, 171.87, 171.41, 171.37,170.90, 153.48, 150.74, 146.37, 146.30, 141.01, 140.09, 138.39, 133.50,133.45, 132.14, 131.62, 131.34, 131.28, 122.80, 122.62, 121.82, 115.89,115.78, 115.72, 115.47, 114.54, 113.79, 113.21, 82.92, 77.08, 61.01,55.69, 53.32, 53.28, 53.18, 53.14, 52.97, 52.90, 52.76, 36.37, 36.15,21.67, 20.20, 20.11, 19.76, 14.79.

C₁₉H₁₈N₂O₄Cl₂I (MW=663.08); mass spectroscopy (MH⁺)=663.

Example 32 Synthesis ofN-[N-(3,4dichlorophenyl)-D,L-alanyl]-(3-iodo)-L-tyrosinemethyl ester

Following General Procedure D and using 3-iodo-L-tyrosine methyl esterhydrochloride (prepared following General Procedure K and using3-iodo-L-tyrosine (Aldrich)) and N-(3,4-dichlorophenyl)-D,L-alanine(from Example A above), the title compound was prepared as a mixture ofstereoisomers about alanine. The reaction was monitored by tlc (Rf=0.29in 10% MeOH/CH₂Cl₂) and purification was by flash chroma,tography (10%methanol/methylene chloride).

NMR data was as follows:

¹H-nmr (CDCl₃) δ=7.37-7.20 (m, 3H), 6.97-6.60 (m, 3H), 6.42 (dd, 1.5H),6.32 (dd, 1.5H), 5.52 (bs, 0.5H), 5.43 (bs, 0.5H), 4.80 (m, 1H), 3.94(dd, 1H), 3.73 (s, 1.5H), 3.70 (s, 1.5H), 3.12 (dd, 0.5H), 2.94 (m,1.5H), 1.48 (d, 1.5H), 1.43 (d, 1.5H).

¹³C-nmr (CDCl₃): δ=173.56, 171.80, 171033, 154.52, 154.47, 145.69,139.15, 138.74, 132.88, 132.71, 130.83, 130.61, 130.40, 130.26, 129.14,128.81, 121.76, 121.73, 115.04, 114.97, 114.86, 113.20, 112.71, 84.96,84.68, 54.85, 54.65, 52.78, 52.60, 52.57, 52.51, 36.29, 36.08, 19.40,19.27.

C₁₉H₁₉N₂O₄Cl₂I (MW=537.18); mass spectroscopy (MH⁺)=538.

Example 33

Following the General Procedures and Examples described herein, thefollowing compound could be prepared:

N-[N-(4-chlorophenyl)-D,L-alanyl]-L-phenylalanine methyl ester

Example 34 Synthesis ofN-[N-(3,4-dichlorophenyl)glycyl]-(S)-2-aminopentanoic acid methyl ester

Following General Procedure D and using N-(3,4-dichlorophenyl)glycine(from Example I above) and L-norvaline methyl ester hydrochloride(Sennchem), the title compound was prepared. The reaction was monitoredby tlc (Rf=0.32 in 50% ethyl acetate/hexanes) and purification was bysilica gel chromatography using ethyl acetate/hexanes as the eluent.

NMR data was as follows:

¹H-nmr (CDCl₃) δ=7.21 (d, J=8.7, 1H), 6.94 (d, J=7.8, 1H), 6.68 (d,J=2.6, 1H), 6.4 (m, 1H), 4.6 (m, 2H), 3.79 (d, J=2.6, 2H), 3.71 (s, 3H),1.7 (m, 2H), 1.2 (m, 2H), 0.88 (t, J=7.3, 7.3, 3H).

¹³C-nmr (CDCl₃): δ=173.3, 170.2, 147.2, 133.6, 131.3, 122.2, 115.0,113.6, 53.0, 52.3, 48.8, 34.8, 19.2, 14.1.

C₁₄H₁₈N₂O₃Cl₂ (MW=333.22); mass spectroscopy (MH⁺)=334.

Example 35 Synthesis ofN-[N-(3,4dichlorophenyl)-D,L-alanyl]-Nε-(hexanoyl)-L-lysine methyl ester

Following General Procedure D and usingN-[N-(3,4-dichlorophenyl)-D,L-alanyl]-L-lysine methyl ester (fromExample 21 above) and hexanoic acid (Aldrich), the title compound wasprepared. The reaction was monitored by tlc (Rf=0.38 in 60% CH₂CH₂/10%hexanes/27% EtOAc/3% MeOH) and purification was by flash chromatographyusing 60% CH₂CH₂/10% hexanes/ 27% EtOAc/3% MeOH as the eluent.

NMR data was as follows:

¹H-nmr (CDCl₃) δ=7.70 (d), 7.25 (m), 7.15 (m), 6.68 (m), 6.42 (m), 5.95(bs), 5.79 (bs), 4.70 (bs), 4.50 (m), 3.80 (m), 3.78 (s), 3.72 (s), 3.45(m), 3.20 (m), 3.05 (m), 2.12 (m), 1.98 (m), 1.80 (m), 1.60 (m), 1.45(m), 1.30 (m), 1.10 (m).

¹³C-nmr (CDCl₃): δ=175.6, 174.4, 174.0, 173.9, 173.7, 173.1, 156.6,146.9 146.8, 133.5, 133.2, 131.2, 131.1, 121.7, 115.4, 115, 23, 115.1,114.0, 113.9, 79.6, 55.1, 54.9, 54.8, 53.0, 52.9, 52.4, 52.0, 42.6,40.9, 39.4, 37.1, 32.1, 31.7, 30.3, 29.4, 28.9, 28.5, 26.9, 25.9, 25.9,23.0, 19.9, 19.7.

C₂₂H₃₃N₃O₄Cl₂ (MW=474.43); mass spectroscopy (MH⁺)=NA.

Example 36 Synthesis ofN-[N-(3,4dichlorophenyl)-D,L-alanyl]-L-phenylalanine amide

Following General Procedure D and using phenylalanine amide (Bachem) andN-(3,4-dichlorophenyl)-D,L-alanine (from Example A above), the titlecompound was prepared as a solid (mp=177-179° C.). This compound wasthen purified by trituration with chloroform.

NMR data was as follows:

¹H-nmr (DMSO-d₆) δ=8.0-8.2 (d, 1H), 7.45 (m, 1H), 7.05-7.30 (m, 7H),7.65-7.72 (m, 1H), 6.24-6.51 (m, 2H), 4.45 (m, 1H), 3.82 (m, 1H), 2.95(m, 1H), 2.78 (m, 1H), 1.05-1.25 (m, 3H).

¹³C-nmr (CDCl₃): δ=173.0, 172.9, 172.8, 172.7, 147.9, 137.7, 131.1,130.3, 129.21, 129.15, 128.0, 127.0, 126.21, 126.19, 116.8, 113.5,113.0, 112.6, 53.4, 53.3, 52.0, 51.8, 37.92, 37.86, 18.9, 18.6.

C₁₈H₁₉N₃O₂Cl₂ (MW=380.28); mass spectroscopy (MH⁺) 380.

Example 37 Synthesis ofN-[N-(3,4dichlorophenyl)-D,L-alanyl]-(S)-2-aminohexan-(N-methyl)-amide

Following General Procedure D and using L-norleucine N-methyl amide(prepared by coupling BOC-L-norleucine (Bachem) with methylamine(Aldrich) using General Procedure E, followed by removal of the BOCgroup using General Procedure F) and N-(3,4-dichlorophenyl)-D,L-alanine,the title compound was prepared. This compound was then purified bywashing with aqueous potassium carbonate.

NMR data was as follows:

¹H-nmr (CD₃OD) δ=6.99 (t, 1H), 6.48 (d, 10.8, 1H), 6.32 (d, 8.7, 1H),4.09 (m, 1H), 3.68 (q, 7.0, 0.5H), 3.59 (q, 7.1, 0.5H), 2.50 (s, 1.5H),2.47 (s, 1.5H), 1.28-1.60 (m, 2H), 1.23 (t, 6.5, 3H), 0.80-1.20 (m, 4H),0.68 (t, 6.7, 1.5H), 0.59 (t, 7.1, 1.5H).

¹³C-nmr (CD₃OD): δ=176.6 (overlapping), 174.54, 174.51, 148.8, 148.5,133.6, 133.5, 131.7, 131.6, 121.0, 120.8, 115.2, 115.1, 114.5, 114.2,55.3, 54.7, 54.3, 54.1, 33.3 (overlapping), 29.0, 28.8, 26.3, 26.2,23.4, 23.3, 19.0 (overlapping), 14.3, 14.2.

C₁₆H₂₃N₃O₂Cl₂ (MW=360.29); mass spectroscopy (MH⁺) 360.

Examples 38 and 39 Synthesis ofN-[N-(3,4dichlorophenyl)-D,L-alanyl]-β-cyclohexylalanine methyl ester

Following General Procedure D and using 3-cyclohexylalanine methyl ester(prepared from β-cyclohexylalanine (Bachem) using General Procedure K)and N-(3,4-dichlorophenyl)-D,L-alanine, the title compound, as a mixtureof diastereomers about alanine, was prepared as an oil. The reaction wasmonitored by tlc (Rf=0.27 (second isomer) and 0.30 (first isomer) in 35%EtOAc/hexanes) and purification was by flash chromatography (35%EtOAc/hexanes).

NMR data was as follows (First Isomer—Example 38):

¹H-nmr (CD₃OD) δ=7.21 (d, 1H), 6.81 (bd, 1H), 6.70 (d, 1H), 6.46 (dd,1H), 4.62 (m, 1H), 4.19 (d, 1H), 3.77 (m, 1H), 3.65 (s, 3H), 1.65-0.90(m, 10H), 1.50 (d, 3H).

¹³C-nmr (CD₃OD): δ=173.78, 173.48, 146.62, 133.45, 131.26, 122.51,115.84, 114.17, 55.64, 52.91, 50.47, 40.18, 34.81, 34.04, 32.88, 26.86,26.71, 26.55, 20.13.

NMR data was as follows (Second Isomer—Example 39):

¹H-nmr (CD₃OD) δ=7.23 (d, 1H), 6.83 (bd, 1H), 6.67 (d, 1H), 6.45 (dd,1H), 4.63 (m, 1H), 4.10 (d, 1H), 3.69 (m, 1H), 3.72 (s, 3H), 1.65-0.90(m, 1OH), l.51(d, 3H).

¹³C-nmr (CD₃OD): δ=173.9,3, 173.56, 146.38, 133.65, 131.34, 122.49,115.35, 113.78, 55.39, 52.95, 50.21, 40.26, 34.61, 34.10, 32.68, 26.82,26.64, 26.41, 19.98.

C₁₉H₂₆N₂O₃Cl₂ (MW=401.34); mass spectroscopy (MH⁺) 401.

Example 40 Synthesis ofN-[N-(3,4-dichlorophenyl)-L-alanyl]-(S)-2-aminohexanamide

Following General Procedure D and using L-norleucine amide (preparedfrom BOC-L-norleucine amide (from Example F above) using GeneralProcedure F) and N-(3,4-dichlorophenyl)-D,L-alanine, the title compoundwas prepared as a solid (mp=156-161° C.).

NMR data was as follows:

¹H-nmr (CD₃OD) δ=6.49 (m, 1H), 6.32 (m, 1H), 1.14 (m, 1H), 3.54-3.71 (m,1H), 0.80-1.62 (m, 9H), C.68 (m, 1.5H), 0.58 (m, 1.5H).

¹³C-nmr (CD₃OD): δ=176.63, 176.56, 148.8, 148.5, 133.6, 133.5, 131.7,131.6, 120.8, 115.2, 115.1, 114.4, 114.2, 55.3, 54.7, 53.9, 53.7, 33.4,33.3, 29.0, 28.6, 23.4, 23.3, 19.03, 18.99, 14.3, 14.2.

C₁₅H₂₁N₃O₂Cl₂ (MW=346.26); mass spectroscopy (MH⁺) 346.

Example 41 Synthesis ofN-[N-(3,4-dichlorophenyl)-D,L-alanyl]-(S)-2-aminohexan-(N,N-dimethyl)-amide

Following General Procedure D and using L-norieucine N,N-dimethyl amide(prepared by coupling BOC-L-norleucine (Bachem) with dimethylamine(Aldrich) using General Procedure E, followed by removal of the BOCgroup using General Procedure F) and N-(3,4-dichlorophenyl)-D,L-alanine,the title S compound was prepared as a solid (ml)=137-160° C.). Thereaction was monitored by tlc (0.20 and 0.24 (5% MeOH in CH₂Cl₂)) andpurifization of this compound was by precipitation from water.

NMR data was as follows:

¹H-nmr (CDCl₃) δ=0.77 (m, 3H), 1.11 (m, 1H), 1.24 (m, 3H), 1.47 (m, 3H),1.40-1.80 (m, 2H), 2.92 and 2.94 (two s, 3H), 3.07 (s, 3H), 3.84 (m,1H), 4.32 (d, J=5.3 Hz, 1H), 4.90 (m, 1H), 6.44 (m, 1H), 6.65 (s, 1H),7.17 (m, 1H), 7.35 (m, 1H).

¹³C-nmr (CDCl₃): δ=13.8, 13.9, 19.3, 19.4, 22.38, 22.45, 27.06, 27.14,32.3, 32.5, 35.7 (possibly overlapping), 37.0, 37.1, 48.6, 48.8, 54.3,54.5, 113.1, 113.5, 114.4, 114.7, 121.1, 121.3, 130.6 (overlapping),132.7, 132.9, 146.0, 146.2, 171.4, 171.5, 172.6, 172.9.

C₁₇H₂₅N₃O₂Cl₂ (MW=374.31); mass spectroscopy (MH⁺) 374.

Example 42 Synthesis ofN-[N-(3,4-dichlorophenyl)-D,L-alanyl]-L-methionine methyl ester

Following General Procedure D and using L-methionine methyl esterhydrochloride (Sigma) and N-(3,4-dichlorophenyl)-D,L-alanine (fromExample A above), the title compound was prepared as a mixture ofdiastereomers. The reaction was monitored by tlc (Rf=0.35 in 43%EtOAc/hexanes) and purification of this compound was by flashchromatography with 43% EtOAc/hexanes.

NMR data was as follows:

¹H-nmr (CDCl₃): δ=7.21 (d, 2H), 6.68 (m, 1H), 6.43 (m, 1H), 4.68 (m,1H), 4.21 (dd, 1H), 3.79 (m, 1H), 3.73 (s, 1.5H), 3.68 (s, 1.5H), 2.46(m, 1H), 2.31 (t, 1H), 2.23-1.88 (m, 2H), 2.06 (s, 1.5H), 1.93 (s,1.5H), 1.50 (d, 3H).

¹³C-nmr (CDCl₃): δ=174.09, 173.81, 172.73, 172.38, 146.60, 146.47,133.43, 131.37, 131.27, 122.36, 122.33, 115.65, 115.31, 114.05, 113.65,55.48, 55.32, 53.19, 53.16, 51.99, 51.68, 31.74, 31.64, 30.62, 30.42,20.10, 19.92, 16.08, 15.91.

C₁₅H₂₀N₂O₂Cl₂S (MW=379.31); mass spectroscopy (MH⁺) 379.

Example 43 Synthesis ofN-[N-(3,5-dichlorophenyl)-D,L-alanyl]-(S)-2-aminohexan-(N,N-dimethyl)-amide

Following General Procedure E and using L-norleucine N,N-dimethyl amide(prepared by coupling BOC-L-norleucine (Bachem) with dimethylamine(Aldrich) using General Procedure E, followed by removal of the BOCgroup using General Procedure F) and N-(3,5-dichlorophenyl)-D,L-alanine(from Example B above), the title compound was prepared. The reactionwas monitored by tlc (Rf=0.25-0.30 in 3% methanol/dichloromethane) andpurification of this compound was by chromatography with 3%methanol/dichloromethane.

NMR data was as follows:

¹H-nmr (CDCl₃): δ=0.8-0.95 (overlapping t, 3H), 1.2-1.8 (m containingoverlapping d at 1.45 and 1.48, 9H), 2.95 (s, 3H), 3.10 (s, 3H), 3.8-3.9(m, 1H), 4.3-4.4 (m, 1H), 4.8-4.95 (m, 1H), 6.45 (s, 2H), 6.6-6.7 (m,1H).

C₁₇H₂₅N₃O₂Cl₂ (MW=374.31).

Example 44 Synthesis ofN-[N-(3,5-dichlorophenyl)-D,L-alanyl]-(S)-2-aminohexanamide

Following General Procedure D and usingN-(3,5-dichlorophenyl)-D,L-alanine (from Example B above) andL-norleucine amide (fronm Example F above), the title compound wasprepared. The reaction was monitored by tlc (Rf=0.15 in 3%methanol/dichloro methane) and purification of this compound was by thinlayer chromatography with 3% methanol/dichloromethane.

NMR data was as follows:

¹H-nmr (CD₃OD): δ=0.9 (t, J=7, 3H), 1.2-1.4 (m, 2H), 1.45 (d, J=7, 3H),1.5-1.7 (m, 1H), 1.75-1.9 (m, 1H), 3.9-4.0 (m, 1H), 4.1-4.3 (m, 1H),4.3-4.4 (m, 1H), 6.5 (bs, 2H), 6.6 (bs, 1H).

C₁₅H₂₁N₃O₂Cl₂ (MW=346.26).

Example 45 Synthesis ofN-[N-(3,5-dichlorophenyl)-D,L-alanyl]-(S)-2-aminohexan-(N-methyl)-amide

Following General Procedure D and usingN-(3,5-dichlorophenyl)-D,L-alanine and L-norleucine N-methyl amide(prepared by coupling BOC-L-norleucine (Bachem) with methylamine(Aldrich) using General Procedure E, followed by removal of the BOCgroup using General Procedure F), the title compound was prepared. Thereacticon was monitored by tlc (Rf=0.25 in 3% methanol/dichloromethane)and purification of this compound was by thin layer chromatography with3% methanol/dichloromethane.

NMR data was as follows:

¹H-nmr (CD₃OD): δ=0.9 (t, J=7, 3H), 1.2-1.4 (m, 2H), 1.45 (d, J=7, 3H),1.5-1.7 (m, 1H), 1.75-1.9 (m, 1H), 2.6-2.7 (m with s at 2.7, 4H),3.8-4.0 (m, 1H), 4.1-4.3 (m, 2H), 6.5 (bs, 2H), 6.6 (bs, 1H)

C₁₆H₂₃N₃O₂Cl₂ (MW=360.29).

Example 46 Synthesis ofN-[N-(3,4-dichlorophenyl)-D,L-alanyl]-L-histidine methyl ester

Following General Procedure D (without the 1N HCl wash) and usingL-histidine methyl ester dihydrochloride (Sigma) andN-(3,4-dichlorophenyl)-D,L-alanine, the title compound was prepared as asolid (mp=55-60° C.). The reaction was monitored by tlc (Rf=0.52 in 10%methanol/methylene chloride) and purification of this compound was byflash chromatography with 50% EtOAc/hexanes.

NMR data was as follows:

¹H-nmr (CDCl₃): δ=8.14 (bd, J=7.02 Hz, 0.5H), 7.79 (bd, 7.57 Hz, 0.5H),7.33 (s, 1H), 7.14 (m, 1H), 6.73 (s, 0.5H), 6.69 (s, 0.5H), 6.59 (m,1H), 6.47 (m, 0.5H), 6.37 (m, 0.5H), 4.74 (m, 1H), 4.33 (m, 1H), 3.79(m, 1H), 3.69 (s, 1.5H), 3.62 (s, 1.54), 3.05 (m, 2H), 1.47 (d, J=7.02Hz, 3H).

¹³C-nmr (CDCl₃): δ=174.35, 174.15, 172.45, 172.08, 146.80, 146.67,135.48, 135.07, 134.65, 133.24, 133.12, 131.13, 131.04, 121.54, 121.49,115.96, 115.78, 115.38, 115.05, 113.90, 113.72, 61.04, 54.98, 53.11,52.97, 52.71, 29.71, 19.43, 21.68, 19.86, 19.84, 14.77.

C₁₆H₁₈N₄O₃Cl₂ (MW=385.25); mass spectroscopy (MH⁺) 385.

Example 47 Synthesis ofN-[N-(quinolin-3-yl)-D,L-alanyl]-(S)-2-aminohexanoic acid methyl ester

Using General Procedure G, followed by hydrolysis set forth in GeneralProcedure C, N-(quinolin-3-yl)-D,L-alanine was prepared. This compoundwas then coupled to L-norleucine methyl ester hydrochloride (Sigma)using General Procedure D to provide for the title compound as an oil.The latter reaction was monitored by tlc (Rf=0.76 in 10%methanol/methylene chloride and 0.07 in 1:1 EtOAc:Hexanes and theproduct was purified by flash chromatography using 10%methanol/methylene chloride as the eluent.

NMR data was as follows:

¹H-nmr (CDCl₃): δ=8.53 (t, J=2.8 Hz, 1H), 7.95 (m, 1H), 7.63 (m, 1H),7.46 (m, 2H), 7.20 (m, 1H), 7.10 (d, J=2.75 Hz, 0.5H), 7.01 (d, J=2.75Hz, 0.5H), 4.60 (m, 2H), 3.94 (m, 1H), 3.71 (s, 1.5H), 3.54 (s, 1.5H),1.90-0.80 (m, 12H).

¹³C-nmr (CDCl₃): δ=173.82, 173.50 ,173.40, 172.96, 143.65, 143.60,143.39, 143.32, 140.34, 140.26, 129.57, 129.49, 127.86, 127.78, 126.94,126.78, 126.54, 113.39, 112.65, 55.60, 55.46, 53.00, 52.86, 52.62,52.28, 32.42, 32.35, 28.03, 27.79, 22.78, 22.62, 20.22, 20.01, 14.41,14.12.

C₁₉H₂₅N₃O₃ (MW=343.43).

Example 48 Synthesis ofN-[N-(benzothiazol-2-yl)-L-alanyl]-(S)-2-aminohexanoic acid methyl ester

Following General Procedure B and using 2-chlorobenzothiazole (Aldrich)and L-alanine (Aldrich), N-(benzothiazol-2-yl)-L-alanine was prepared.This compound was then coupled to L-norleucine methyl esterhydrochloride (Sigma) using General Procedure D (without the 1N HClwash) to provide for the title compound as a solid (mp=99-120° C.). Thelatter reaction was monitored by tlc (Rf=0.42 in 1:1 EtOAc:Hexanes) andthe product was purified by preparative plate chromatography using 1:1EtOAc:Hexanes and 5:95 MeOH:dichloromethane as the eluent.

NMR data was as follows:

¹H-nmr (CDCl₃): δ=7.66-7.03 (m, 6H), 4.69 (m, 1H), 4.58 (m, 1H), 3.72(s, 1.9H), 3.61 (s, 1.1H), 1.91-1.50 (m, 5H), 1.32-1.08 (m, 4H),0.87-0.65 (m, 3H).

¹³C-nmr (CDCl₃): δ=175.8, 170.3, 166.8, 160.2, 152.3, 148.4, 132.1,131.1, 126.8, 126.5, 124.5, 122.6, 172.0, 121.4, 120.9, 119.4, 54.3,54.2, 53.0, 52.9, 3.5, 28.1, 28.0, 23.9, 22.9, 19.0, 18.8, 14.2.

C₁₇H₂₃N₃O₃S (MW=349.46): mass spectroscopy (MH⁺ 350).

Example 49 Synthesis of N-[N-(3,5-difluorophenyl)-D,L-alanyl]-L-alaninemethyl ester

Following General Procedure E and using L-alanine methyl esterhydrochloride (Sigma) and N-(3,5-difluorophenyl)-D,L-alanine (fromExample C above), the title compound was prepared as a solid (mp=93-95°C.). The reaction was monitored by tlc (Rf=0.4 in 3% methanol/methylenechloride) and purification of this compound was by flash chromatographywith 3% methanol/methylene chloride.

NMR data was as follows:

¹H-nmr (CDCl₃): δ=6.9 (q), 6.25 (t), 6.10 (q), 5.3 (s), 4.6 (m), 4.25(m), 33.7-3.8 (m), 1.8 (s), 1.5 (d), 1.4 (q), 1.25 (s).

¹³C-nmr (CDCl₃): δ=173.78, 173.51, 173.44, 173.27, 166.24, 166.09,163.04, 162.83, 149.41, 149.37, 97.47, 97.34, 97.20, 97.09, 96.82,95.08, 95.03, 94.73, 94.69, 94.39, 94.34, 55.27, 55.22, 53.10, 53.02,48.46, 48.35, 19.99, 19.87, 18.72, 18.66.

C₁₃H₁₆N₂O₃F₂ (MW=286.3); mass spectroscopy (MH⁺) 287.

Example 50 Synthesis ofN-[N-(3,5-difluorophenyl)-D,L-alanyl]-(S)-2-aminohexanoic acid methylester

Following General Procedure E and using L-norleucine methyl esterhydrochloride (Sigma) and N-(3,5-difluorophenyl)-D,L-alanine, the titlecompound was prepared as a solid (mp=93-95° C.). The reaction wasmonitored by tlc (Rf=0.6 in 3% methanol/methylene chloride) andpurification of this compound was by flash chromatography with 3%methanol/methylene chloride.

NMR data was as follows:

¹H-nmr (CDCl₃): δ=6.95 (d), 6.85 (d), 6.25 (t), 6.15 (t), 4.6 (m), 4.3(m), 3.8 (m), 3.75 (s), 3.70 (s), 1.8 (m), 1.65 (m), 1.55 (d), 1.3 (m),1.1 (m), 0.85 (t), 0.80 (t).

¹³C-nmr (CDCl₃): δ=173.64, 173.42, 173.35, 173.04, 149.38, 149.23,97.52, 97.21, 97.14, 96.83, 95.10, 95.05, 94.75, 94.70, 94.41, 77.61,77.19, 55.34, 55.25, 52.97, 52.87, 52.58, 52.25, 32.41, 27.96, 27.74,22.79, 22.68, 20.05, 19.87, 14.39, 14.25.

C₁₆H₂₂N₂O₃F₂ (MW=328.3); mass spectroscopy (MH⁺) 329.

Example 51 Synthesis ofN-[N-(3,4dichlorophenyl)-L-alanyl]-(S)-2-aminohexanamide

Following General Procedure D (using DMF as the solvent and ethylacetate for extraction, and without the 1N HCl wash) and usingL-norleucine amide (prepared from BOC-L-norleucine amide (from Example Fabove) using General Procedure F) and N-(3,4-dichlorophenyl)-L-alanine(prepared from 3,4-dichloroaniline (Aldrich) and isobutyl R-(+)-lactate(Aldrich) using General Procedure J, followed by hydrolysis usingGeneral Procedure C), the title compound was prepared as a solid(mp=184-186° C.). The reaction was monitored by tlc (Rf=0.48 in 12%methanol/methylene chloride) and purification of this compound was bypreparative plate chromatography using 12% methanol/methylene chlorideas eluent.

NMR data was as follows:

¹H-nmr (CD₃OD): δ=6.97 (d, J=8.79 Hz, 1H), 6.51 (d, J=2.68 Hz, 1H), 6.32(dd, J=8.73 Hz, J=2.68 Hz, 1H), 4.14 (m, 1H), 3.67 (q, J=6.96 Hz, 1H),1.40 (m, 10H), 0.70 (m, 3H)

¹³C-nmr (CDCl₃): δ=177.19, 177.11, 149.41, 134.05, 132.13, 121.38,115.82, 114.96, 55.26, 54.48, 33.92, 29.54, 23.95, 19.58, 14.83.

C₅H₂₁N₃O₂Cl₂ (MW=346.26); mass spectroscopy (MH⁺) 346.

Example 52 Synthesis ofN-[N-(3,4-dichlorophenyl)-D,L-alanyl]-(S)-2-aminohexan-(N-benzyl)-amide

Following General Procedure H above and usingN-[N-(3,4-dichlorophenyl)-D,L-alanyl]-(S)-2-aminohexanoic acid methylester (from Example 15 above) and benzylamire (Aldrich), the titlecompound was prepared as a solid (mp=141-146° C.). The reaction wasmonitored by tlc on silica gel (Rf=0.32 in 5% methanol/methylenechloride) and purification was by preparative plate chromatography(silica gel using 5% methanol/methylene chloride as eluent).

NMR data was as follows:

¹H-nmr (CDCl₃): δ=7.6 (m, 2H), 7.2 (m, 6H), 6.6 (m, 1H), 6.3 (m, 1H),4.47 (m, 4H), 3.75 (m, 1H), 1.28 (m, 12H).

¹³C-nmr (CDCl₃): δ=174.56, 174.50, 172.39, 172.32, 146.78, 146.65,138.38, 133.43, 133.38, 131.22, 129.21, 128.06, 121.98, 121.72, 121.66,115.21, 115.08, 113.73, 113.55, 54.94, 54.36, 53.60, 53.22, 43.95,33.10, 32.98, 28.24, 27.95, 22.96, 22.90, 19.78, 19.70, 14.49, 14.41.

C₂₂H₂₇Cl₂N₃O₂ (MW=436.39); mass spectroscopy (MH⁺) 436.

Example 53 Synthesis ofN-[N-(3,4-dichlorophenyl)-D,L-alanyl]-(S)-2-amino-2-phenylethanol

Following General Procedure E and usingN-(3,4-dichlorophenyl)-D,L-alanine (from Example A above) and(S)-(+)-2-phenylglycinol (Aldrich), the title compound was prepared as asolid (mp=66-70° C.). The reaction was monitored by tlc on silica gel(Rf=0.25 in 5% methanol/methylene chloride) and purification was byflash column chromatography (silica gel using 5% methanol/methylenechloride as eluent).

NMR data was as follows:

¹H-nmr (CDCl₃): δ=7.4-7.1 (m, 6H), 6.75 (d, J=3 Hz, 1H), 6.5-6.4 (m,1H), 5 (m, 1H), 4.2-4.0 (m, J=4 Hz, 1H), 3.8 (2H), 1.7 (s, 1H), 1.55 (m,3H).

¹³C-nmr (CDCl₃): δ=174, 146, 139, 134, 131.8, 129.5, 128.5, 127, 123,116, 114, 112, 67, 56.5, 55.5, 20.

C₁₆H₁₈Cl₂N₂O₂ (MW=341); mass spectroscopy (MH⁺) 342.

Examples 54 and 55 Synthesis ofN-[N-(3,5-dichlorophenyl)-D,L-phenylglycyl]-L-alanine methyl ester

Following General Procedure E and usingN-(3,5-dichlorophenyl)-D,L-phenylglycine (from Example J above) andL-alanine methyl ester hydrochloride (Sigma), the title compound wasprepared. The reaction was monitored by tlc (Rf=0.95 in 3%methanol/methylene chloride) and purification of this compound was byrecrystallization from EtOAc, hexane and ether. Two partially separateddiastereomeric mixtures were obtained.

NMR data was as follows:

¹H-nmr (CDCl₃—75% isomer A/25% isomer B): δ=7.45-7.35 (m, 5H), 6.7 (m,2H), 6.47 (m, 2H), 5.1-5.0 (dd, J=3 Hz, 1H), 4.75 (d, J =3.5 Hz, 1H),4.65-4.5 (m, 7.2 Hz 1H), 3.75-3.68 (2 s in a ratio of 3:1, 3H), 1.43-1.3(2 d in a ratio of 3:1, J=7,2 Hz, 3H).

¹³C-nmr (CDCl₃—75% isomer A/25% isomer B): δ=173.27, 170.24, 148.61,138.23, 136.07, 136.00, 130.11, 129.60, 129.58, 127.83, 127.69, 119.10,112.68, 112.56, 78.03, 63.27, 53.20, 48.94, 18.85.

¹H-nmr (CDCl₃—25% isomer A/75% isomer B): δ=7.45-7.35 (m, 5H), 6.7 (m,2H), 6.47(m, 2H), 5.1-5.0 (2xd, J=3 Hz, 1H), 4.75 (d, J =3.5 Hz, 1H),4.65-4.5 (m, J=7.2 Hz, 1H), 3.75-3.68 (2 s in a ratio of 1:3, 3H),1.43-1.3 (2 d in a ratio of 1:3, J=7.2 Hz, 3H).

¹³C-nmr (CDCl₃—25% isomer Al75% isomer B): δ=173.27, 170.24, 148.61,138.23, 136.07, 136.00, 130.11, 129.60, 129.58, 127.83, 127.69, 119.10,112.68, 112.56, 78.03, 63.27, 53.20, 48.94, 18.85.

C₁₈H₁₈N₂O₃Cl₂ (MW=381.26); mass spectroscopy (MH⁺) 381.

Example 56 Synthesis ofN-[N-(3,4dichlorophenyl)-D,L-alanyl]-(S)-2-aminohexanol

Following General Procedure I above and usingN-[N-(3,4-dichlorophenyl)-D,L-alanyl]-(S)-2-aminohexanoic acid methylester (from Example 15 above), the title compound was prepared as anoil. The reaction was monitored by tlc on silica gel (Rf=0.16 and 0.17in 5% methanol/methylene chloride) and purification was by preparativeplate chromatography (silica gel using 5% methanol/methylene chloride aseluent).

NMR data was as follows:

¹H-nmr (CD₃OD): δ=7.20 (d, 1H), 6.79 (m, 1H), 6.68 (dd, 1H), 6.43 (d,1H), 4.42 (bd, 0.6H), 4.30 (bd, 0.4H), 3.89 (m, 1H), 3.75 (m, 1H),3.70-3.40 (m, 2H), 1.60-0.95 (m, 9H), 0.90-0.70 (m, 3H)

¹³C-nmr (CD₃OD): δ=174.42, 174.17, 146.06, 145.96, 132.89, 132.85,130.74, 130.69, 121.64, 121.49, 114.98, 114.70, 113.14, 113.08, 65.42,65.11, 55.00, 54.76, 51.69, 51.48, 30.67, 30.59, 28.16, 28.00, 22.48,22.36, 19.44, 13.92, 13.82.

C₁₅H₂₂Cl₂N₂O₂ (MW=333.26); mass spectroscopy (MH⁺) 333.

Example 57 Synthesis ofN-[N-(3,5-dichlorophenyl)-D,L-alanyl]-(S)-2-amino-2-phenylethanol

Following General Procedure E and usingN-(3,5-dichlorophenyl)-D,L-alanine (from Example B above) and(S)-(+)-2-phenylglycinol (Aldrich), the title compound could beprepared.

Example 58 Synthesis ofN-[N-(3,5-dichlorophenyl)-L-alanyl]-L-phenylglycine tert-butyl ester

Following General Procedure D (without the 1N HCl wash) and usingN-(3,5-dichlorophenyl)-L-alanine (prepared from 3,5-dichloroaniline(Aldrich) and isobutyl R-(+)-lactate (Aldrich) using General ProcedureJ, followed by hydrolysis using General Procedure C) and L-phenylglycinetert-butyl ester hydrochloride (Bachem), the title compound wasprepared. The reaction was monitored by tlc (Rf=0.39 in 25%EtOAc/Hexanes) and purification of this compound was by preparativeplate chromatography using 25% EtOAc/Hexanes.

NMR data was as follows:

¹H-nmr (CDCl₃): δ=7.55 (d, J=7.39 Hz, 1H), 7.30 (s, 5H), 6.73 (t, J=1.68Hz, 1H), 6.46 (d, J=1.71 Hz, 2H), 5.45 (d, J=7.45 Hz, 1H), 4.47 (d,J=5.19 Hz, 1H), 3.82 (m, 1H), 1.40 (d, J=6.96 Hz, 3H), 1.34 (s, 9H).

¹³C-nmr (CDCl₃): δ=173.23, 169.92, 148.93, 137.43, 136.07, 129.40,128.85, 127.40, 119.04, 112.48, 83.42, 57.37, 54.70, 28.29, 19.79.

C₂₁H₂₄N₂O₃Cl₂ (MW=423.34); mass spectroscopy (MH⁺) 423.

Example 59 Synthesis of N-[N-(3,5-di-(trifluoromethyl)phenyl)-L-alanyl]-L-phenylglycine tert-butyl ester

Following General Procedure D and usingN-[3,5-di-(trifluoromethyl)phenyl]-L-alanine (from Example G above) andL-phenylglycine tert-butyl ester hydrochloride (Bachem), the titlecompound was prepared. The reaction was monitored by tlc (Rf=0.46 in 25%EtOAc/Hexanes).

NMR data was as follows:

¹H-nmr (CDCl₃): δ=7.39 (d, J=7.39 Hz, 1H), 7.29 (s, 5H), 6.96 (s, 2H),5.45 (d, J=7.51 Hz, 1H), 4.69 (d, J=5.31 Hz, 1H), 3.95 (m, 1H), 1.48 (d,J=6.96 Hz, 3H), 1.33 (s, 9H).

¹³C-nmr (CDCl₃): δ=172.7, 169.9, 147.9, 137.3, 132.8, 132.4, 129.42,129.34, 129.31, 128.9, 127.4, 127.2, 127, 122.1, 113.50, 113.47, 112.34,112.29, 112.24, 83.5, 57.3, 54.6, 28.34, 28.30, 28.2, 19.8.

C₂₃H₂₄N₂O₃F₆ (MW=490.45).

Example 60 Synthesis ofN-[N-(3,5-dimethoxyphenyl)-D,L-alanyl]-(S)-2-ammohexanoic acid methylester

Following General Procedure E (washing with dilute HCl and extractingwith EtOAc) and using N-(3,5-dimethoxyphenyl)-D,L-alanine (from ExampleH above) and L-norleucine methyl ester hydrochloride (Sigma), the titlecompound was prepared as a light yellow oil. The reaction was monitoredby tlc (Rf=0.3 in 30% EtOAc/Hexanes).

NMR data was as follows:

¹H-nmr (CDCl₃): δ=0.6-0.9 (two triplets at 0.72 and 0.82, J=7 Hz, 3H),1.0-1.9 (m, 9H), 3.6-3.7 (four singlets at 3.60, 3.65, 3.66 and 3.67,10H), 3.7-3.8 (m, 1H), 4.6-4.7 (m, 1H), 5.7-5.95 (m, 3H), 7.1-7.3 (m,1H).

¹³C-nmr (CDCl₃): δ=14.21, 14.35, 19.8, 20.0, 22.69, 22.74, 27.8, 28.0,32.20, 32.45, 52.18, 52.57, 52,65, 52.78, 55.31, 55.52, 55.59, 55.63,91.6, 91.8, 92.86, 93.24, 149.02, 149.27, 162.11, 162.18, 173.02,173.44, 174.47, 174.82.

C₁₈H₂₈N₂O₅ (MW=352.43).

Example 61 Cellular Screen for the Detectioin of Inhibitors of β-AmyloidProduction

Numerous compounds of formula I above were assayed for their ability toinhibit β-amyloid production in a zell line possessing the Swedishmutation. This screening assay employed cells (K293=human kidney cellline) which were stably transfected with the gene for amyloid precursorprotein 751 (APP751) containing the double mutation Lys₆₅₁,Met₆₅₂ toAsn₆₅₁Leu₆₅₂ (APP751 numbering) in the manner described in InternationalPatent Application Publication No. 94/10569⁸ and Citron et al.¹¹. Thismutation is commonly called the Swedish mutation and the cells,designated as “293 751 SWE”, were plated in Corning 96-well plates at1.5-2.5×10⁴ cells per well in Dulbecco's minimal essential media (Sigma,St. Louis, Mo.) plus 10% fetal bovine serum. Cell number is important inorder to achieve β-amyloid ELISA results within the linear range of theassay (˜0.2 to 2.5 ng per mL).

Following overnight incubation at 37° C. in an incubator equilibratedwith 10% carbon dioxide, media were removed and replaced with 200 μL ofa compound of formula I (drug) containing media per well for a two hourpretreatment period and cells were incubated as above. Drug stocks wereprepared in 100% DMSO such that at the final drug concentration used inthe treatment, the concentration of dimethyl sulfoxide did not exceed0.5% and, in fact, usually equaled 0.1%.

At the end of the pretreatment period, the media were again removed andreplaced with fresh drug containing media as above and cells wereincubated for an additional two hours. After treatment, plates werecentrifuged in a Beckman GPR at 1200 rpm for five minutes at roomtemperature to pellet cellular debris from the conditioned media. Fromeach well, 100 μL of conditioned media or appropriate dilutions thereofwere transferred into an ELISA plate precoated with antibody 266 [P.Seubert, Nature (1992) 359:325-327]against amino acids 13-28 ofβ-amyloid peptide as described in International Patent ApplicationPublication No. 94/10569⁸ and stored at 4° C. overnight. An ELISA assayemploying labelled antibody 6C6 [P. Seubert, Nature (1992) 359:325-327]against amino acids 1-16 of β-amyloid peptide was run the next day tomeasure the amount of β-amyloid peptide produced.

Cytotoxic effects of the compounds were measured by a modification ofthe method of Hansen, et al.¹². To the cells remaining in the tissueculture plate was added 25 μL of a3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)(Sigma, St. Louis, Mo.) stock solution (5 mg/mL) to a finalconcentration of 1 mg/mL. Cells were incubated at 37° C. for one hour,and cellular activity was stopped by the addition of an equal volume ofMMT lysis buffer (20% w/v sodium dodecylsulfate in 50%dimethylformamide, pH 4.7). Complete extraction was achieved byovernight shaking at room temperature. The difference in the OD_(562nm)and the OD_(650nm) was measured in a Molecular Device's UV_(max)microplate reader as an indicator of the cellular viability.

The results of the β-amyloid peptide ELISA were fit to a standard curveand expressed as ng/mL β-amyloid peptide. In order to normalize forcytotoxicity, these results were divided by the MMT results andexpressed as a percentage of the results from a drug free control. Allresults are the mean and standard deviation of at least six replicateassays.

The test compounds were assayed for β-amyloid peptide productioninhibition activity in cells using this assay. The results of this assaydemonstrate that, each of the compounds of Examples 1-60 inhibit theβ-amyloid peptide production by at least 30% as compared to control.

Example 62 In Vivo Suppression of β-Amyloid Release and/or Synthesis

This example illustrates how the compounds of this invention could betested for in vivo suppression of β-amyloid release and/or synthesis.For these experiments, 3 to 4 month old PDAPP mice are used [Games etal., (1995) Nature 373:523-5271. Depending upon which compound is beingtested, the compound is usually formulated at either 5 or 10 mg/mL.Because of the low solubility factors of the compounds, they may beformulated with various vehicles, such as corn oil (Safeway, South SanFrancisco, Calif.); 10% ethanol in corn oil;2-hydroxypropyl-β-cyclodextrin (Research Biochemicals International,Natick Mass.); and carboxymethylcellulose (Sigma Chemical Co., St. LouisMo.).

The mice are dosed subcutaneously with a 26 gauge needle and 3 hourslater the animals are euthanized via CO₂ narcosis and blood is taken bycardiac puncture using a 1 cc 25G ⅝″ tuberculin syringe/needle coatedwith solution of 0.5 M EDTA, pH 8.0. The blood is placed in aBecton-Dickinson vacutainer tube containing EDTA and spun down for 15minutes at 1500×gravity at 5° C. The brains of the mice are then removedand the cortex and hippocampus are dissected out and placed on ice.

1. Brain Assay

To prepare hippocampal and cortical tissue for enzyme-linkedimmunosorbent assays (ELISAs) each brain region is homogenized in 10volumes of ice cold guanidine buffer (5.0 M guanidine-HCl, 50 mMTris-HCl, pH 8.0) using a Kontes motorized pestle (Fisher, PittsburghPa.). The homogenates are gently rocked on a rotating platform for threeto four hours at room temperature and stored at −20° C. prior toquantitation of β-amyloid.

The brain homogenates are diluted 1:10 with ice-cold casein buffer[0.25% casein, phosphate buffered saline (PBS), 0.05% sodium azide, 20μg/mL aprotinin, 5 mM EDTA, pH 8.0, 10 μg/mL leupeptin], therebyreducing the final concentration of guanidine to 0.5 M, beforecentrifugation at 16,000×gravity for 20 minutes at 4° C. The β-amyloidstandards (1-40 or 1-42 amino acids) were prepared such that the finalcomposition equaled 0.5 M guanidine in the presence of 0.1% bovine serumalbumin (BSA).

The total β-amyloid sandwich ELISA, quantitating both β-amyloid (aa1-40) and β-amyloid (aa 1-42) consists of two monoclonal antibodies(mAb) to β-amyloid. The capture antibody, 266 [P. Seubert, Nature (1992)359:325-327], is specific to amino acids 13-28 of β-amyloid. Theantibody 3D6 [Johnson-Wood et al., PNAS USA (1997) 94:1550-1555], whichis specific to amino acids 1-5 of β-amyloid, is biotinylated and servedas the reporter antibody in the assay. The 3D6 biotinylation procedureemploys the manufacturer's (Pierce, Rockford Ill.) protocol forNHS-biotin labeling of immunoglobulins except that 100 mM sodiumbicarbonate, pH 8.5 buffer is used. The 3D6 antibody does not recognizesecreted amyloid precursor protein (APP) or ful-length APP but detectsonly β-amyloid species with an amino terminal aspartic acid. The assayhas a lower limit of sensitivity of ˜50 pg/mL (11 pM) and shows nocross-reactivity to the endogenous murine β-amyloid peptide atconcentrations up to 1 ng/mL.

The configuration of the sandwich ELISA quantitating the level ofβ-amyloid (aa 1-42) employs the mAb 21F12 [Johnson-Wood et al., PNAS USA(1997) 94:1550-1555] (which recognizes amino acids 33-42 of β-amyloid)as the capture antibody. Biotinylated 3D6 is also the reporter antibodyin this assay which has a lower limit of sensitivity of ˜125 pg/mL (28pM).

The 266 and 21F12 capture mAbs are coated at 10 μg/mL into 96 wellimmunoassay plates (Costar, Cambidge Mass.) overnight at roomtemperature. The plates are then aspirated and blocked with 0.25% humanserum albumin in PBS buffer for at least 1 hour at room temperature,then stored desiccated at 4° C. until use. The plates are rehydratedwith wash buffer (Tris-buffered saline, 0.05% Tween 20) prior to use.The samples and standards are added to the plates and incubatedovernight at 4° C. The plates are washed >3 times with wash bufferbetween each step of the assay. The biotinylated 3D6, diluted to 0.5μg/mL in casein incubation buffer (0.25% casein, PBS, 0.05% Tween 20, pH7.4) is incubated in the well for 1 hour at room temperature. Avidin-HRP(Vector, Burlingame Calif.) diluted 1:4000 in casein incubation bufferis added to the wells for 1 hour at room temperature. The calorimetricsubstrate, Stow TMB-ELISA (Pierce, Cambridge Mass.), is added andallowed to react for 15 minutes, after which the enzymatic reaction isstopped with addition of 2 N H₂SO₄. Reaction product is quantified usinga Molecular Devices Vmax (Molecular Devices, Menlo Park Calif.)measuring the difference in absorbance at 450 nm and 650 nm.

2. Blood Assay

The EDTA plasma is diluted 1:1 in specimen diluent (0.2 g/L sodiumphosphate.H₂O (monobasic), 2.16 g/L sodium phosphate.7H₂O (dibasic), 0.5g/L thimerosal, 8.5 g/L sodium chloride, 0.5 mL Triton X-405, 6.0 g/Lglobulin-free bovine serum albumin; and water). The samples andstandards in specimen diluent are assayed using the total β-amyloidassay (266 capture/3D6 reporter) described above for the brain assayexcept the specimen diluent was used instead of the casein diluentsdescribed.

From the foregoing description, various modifications and changes in thecomposition and method will occur to those skilled in the art. All suchmodifications coming within the scope of the appended claims areintended to be included therein.

1 43 amino acids amino acid linear peptide 1 Asp Ala Glu Phe Arg His AspSer Gly Tyr Glu Val His His Gln Lys 1 5 10 15 Leu Val Phe Phe Ala GluAsp Val Gly Ser Asn Lys Gly Ala Ile Ile 20 25 30 Gly Leu Met Val Gly GlyVal Val Ile Ala Thr 35 40

What is claimed is:
 1. A pharmaceutical composition comprising apharmaceutically inert carrier and a pharmaceutically effective amountof a compound of formula I:

wherein: R¹ is selected from the group consisting of (a) phenyl, (b) asubstituted phenyl group of formula II:

wherein R^(c) is selected from the group consisting of acyl, alkyl,alkoxy, alkylalkoxy, azido, cyano, halo, hydrogen, nitro, trihalomethyl,thioalkoxy, and wherein R^(b) and R^(c) are fused to form a heteroarylor heterocyclic ring with the phenyl ring, R^(b) and R^(b′) areindependently selected from the group consisting of hydrogen, halo,nitro, cyano, trihalomethyl, alkoxy, and thioalkoxy with the provisothat when R^(c) is hydrogen, then R^(b) and R^(b′) are either bothhydrogen or both substituents other than hydrogen, (c) 2-naphthyl, (d)2-naphthyl substituted at the 4, 5, 6, 7 and/or 8 positions with 1 to 5substituents selected from the group consisting of alkyl, alkoxy, halo,cyano, nitro, trihalomethyl, thioalkoxy, aryl, and heteroaryl, (e)heteroaryl, and (f) substituted heteroaryl containing 1 to 3substituents selected from the group consisting of alkyl, alkoxy, aryl,aryloxy, cyano, halo, nitro, heteroaryl, thioalkoxy and thioaryloxyprovided that said substituents are not ortho to the heteroarylattachment to the —NH group; R² is selected from the group consisting ofhydrogen, alkyl of from 1 to 4 carbon atoms, alkylalkoxy of from 1 to 4carbon atoms, alkylthioalkoxy of from 1 to 4 carbon atoms, aryl,heteroaryl, substituted aryl and substituted heteroaryl provided thatthe substituents are not ortho to the attachment of the aryl orheteroaryl atom to the carbon atom; R³ is selected from the groupconsisting of alkyl, alkenyl, alkynyl, aryl, cycloalkyl, cycloalkenyl,heteroaryl, substituted alkyl, substituted alkenyl, substituted alkynyl,and heterocyclic; X is —C(O)Y where Y is selected from the groupconsisting of (a) alkyl, (b) substituted alkyl with the proviso that thesubstitution on said substituted alkyl does not include α-haloalkyl,α-diazoalkyl or α-OC(O)alkyl groups, (c) alkoxy or thioalkoxy, (d)substituted alkoxy or substituted thioalkoxy, (e) hydroxy, (f) aryl, (g)heteroaryl, (h) heterocyclic, (i) —NR′R″ where R′ and R″ areindependently selected from the group consisting of: hydrogen, alkyl,substituted alkyl of from 1 to 10 carbon atoms, having from 1 to 3substituents selected from the group consisting of alkoxy, substitutedalkoxy, acyl, acylamino, acyloxy, amino, aminoacyl, aminoacyloxy, cyano,halogen, carboxyl, carboxylalkyl, cycloalkyl, oxyacylamino, thiol,thioalkoxy, substituted thioalkoxy, aryl, heteroaryl, heterocyclic,nitro, and mono- and di-alkylamino, mono- and di(substitutedalkyl)amino, mono- and di-cycloalkylamino, mono- and di-arylamino, mono-and di-heteroaryl-amino, mono- and di-heterocyclic amino, andunsymmetric di-substituted amines having different substituents selectedfrom alkyl, substituted alkyl, cycloalkyl, aryl, heteroaryl andheterocyclic, cycloalkyl, aryl, heteroaryl, heterocyclic, and where R′and R″ are joined to form a cyclic group having from 2 to 8 carbon atomsoptionally containing 1 to 2 additional heteroatoms selected from thegroup consisting of oxygen, sulfer and nitrogen and optionallysubstituted with one or more alkyl or alkoxy groups, and when R³contains at least 3 carbon atoms, X can also be —CR⁴R⁴Y′ WHERE each R⁴is independently selected from the group consisting of hydrogen, alkyl,cycloalkyl, aryl, heteroaryl and heterocyclic and Y′ is selected fromthe group consisting of amino, thiol, —OC(O)R⁵, —SSR⁵, —SSC(O)R⁵ whereR⁵ is selected from the group consisting of alkyl, substituted alkyl,cycloalkyl, aryl, heteroaryl and heterocyclic, and with the proviso thatwhen R¹ is 3,4-dichlorophenyl, R² is methyl, and R³ is benzyl derivedfrom D-phenylalanine, then X is not —C(O)OCH₃.
 2. The pharmaceuticalcomposition according to claim 1 wherein R¹ is phenyl, 2-naphthyl,quinolin-3-yl, benzothiazol-6-yl, and 5-indolyl.
 3. The pharmaceuticalcomposition according to claim 1 wherein R¹ is a substituted phenylgroup of the formula:

wherein R^(c) is selected from the group consisting of acyl, alkyl,alkoxy, alkylalkoxy, azido, cyano, halo, hydrogen, nitro, trihalomethyl,thioalkoxy, and wherein R^(b) and R^(c) are fused to form a heteroarylor heterocyclic ring with the phenyl ring, R^(b) and R^(b′) areindependently selected from the group consisting of hydrogen, halo,nitro, cyano, trihalomethyl, alkoxy, and thioalkoxy with the provisothat when R^(c) is hydrogen, then R^(b) and R^(b′) are either bothhydrogen or both substituents other than hydrogen.
 4. The pharmaceuticalcomposition according to claim 1 wherein R¹ is a substituted 2-naphthylsubstituted at the 4, 5, 6, 7 and/or 8 positions with 1 to 5substituents selected from the group consisting of alkyl, alkoxy, halo,cyano, nitro, trihalomethyl, thioalkoxy, aryl, and heteroaryl.
 5. Thepharmaceutical composition according to claim 1 wherein R¹ is asubstituted heteroaryl containing 1 to 3 substituents selected from thegroup consisting of alkyl, alkoxy, aryl, aryloxy, cyano, halo, nitro,heteroaryl, thioalkoxy, thioaryloxy provided that said substituents arenot ortho to the heteroaryl attachment to the —NH group.
 6. Thepharmaceutical composition according to claim 5 wherein R¹ is a4-substituted, a 3,5-disubstituted or 3,4-disubstituted phenyl.
 7. Thepharmaceutical composition according to claim 6 wherein R¹ is a3,5-disubstituted phenyl.
 8. The pharmaceutical composition according toclaim 7 wherein the 3,5-disubstituted phenyl is selected from the groupconsisting of 3,5-dichlorophenyl, 3,5-difluorophenyl,3,5-di(trifluoromethyl)phenyl and 3,5-dimethoxyphenyl.
 9. Thepharmaceutical composition according to claim 6 wherein R¹ is a3,4-disubstituted phenyl.
 10. The pharmaceutical composition accordingto claim 9 wherein the 3,4-disubstituted phenyl is selected from thegroup consisting of 3,4-dichlorophenyl, 3,4-difluorophenyl,3-(trifluoromethyl)-4-chlorophenyl, 3-chloro-4-cyanophenyl,3-chloro-4-iodophenyl and 3,4-methylenedioxyphenyl.
 11. Thepharmaceutical composition according to claim 6 wherein R¹ is a4-substituted phenyl.
 12. The pharmaceutical composition according toclaim 11 wherein the 4-substituted phenyl is selected from the groupconsisting of 4-azidophenyl, 4-bromophenyl, 4-chlorophenyl,4-cyanophenyl, 4-ethylphenyl, 4-fluorophenyl, 4-iodophenyl,4-(phenylcarbonyl)phenyl, and 4-(1-ethoxy)ethylphenyl.
 13. Thepharmaceutical composition according to claim 1 wherein R¹ is2-methylquinolin-6-yl.
 14. The pharmaceutical composition according toclaim 1 wherein R² is selected from the group consisting of alkyl offrom 1 to 4 carbon atoms, alkylalkoxy of from 1 to 4 carbon atoms,alkylthioalkoxy of from 1 to 4 carbon atoms and aryl.
 15. Thepharmaceutical composition according to claim 14 wherein R² is selectedfrom the group consisting of methyl, ethyl, n-propyl, iso-propyl,n-butyl, iso-butyl, —CH₂CH₂SCH₃ and phenyl.
 16. The pharmaceuticalcomposition according to claim 1 wherein R³ is an alkyl group.
 17. Thepharmaceutical composition according to claim 16 wherein the alkyl groupis selected from the group consisting of methyl, ethyl, n-propyl,iso-propyl, n-butyl, iso-butyl and sec-butyl.
 18. The pharmaceuticalcomposition according to claim 1 wherein R³ is a substituted alkylgroup.
 19. The pharmaceutical composition according to claim 18 whereinthe substituted alkyl group is selected from the group consisting ofα-hydroxyethyl, —CH₂-cyclohexyl, benzyl, p-hydroxybenzyl,3-iodo-4-hydroxybenzyl, 3,5-diiodo-4-hydroxybenzyl, —CH₂-indol-3-yl,—(CH₂)₄—NH-BOC, —(CH₂)₄—NH₂, —CH₂-(1-N-benzyl-imidazol-4-yl),—CH₂-imidazol-4-yl, —CH₂CH₂SCH₃, —(CH₂)₄NHC(O)(CH₂)₃CH₃, and—(CH₂)_(y)C(O)OR⁵ where y is 1 or 2 and R⁵ is hydrogen, methyl, ortert-butyl.
 20. The pharmaceutical composition according to claim 1wherein X is —C(O)Y wherein Y is selected from the group consisting ofalkoxy and thioalkoxy.
 21. The pharmaceutical composition according toclaim 1 wherein Y is alkoxy selected from the group consisting ofmethoxy, ethyoxy, n-propoxy, iso-propoxy, n-butoxy, iso-butoxy, andtert-butoxy.
 22. The pharmaceutical composition according to claim 1wherein X is —C(O)Y and Y is —NR′R″ where R′ and R″ are independentlyselected from the group consisting of hydrogen, alkyl, substitutedalkyl, cycloalkyl, aryl, heteroaryl, heterocyclic, and where R′ and R″are joined to form a cyclic group having from 2 to 8 carbon atomsoptionally containing 1 to 2 additional heteroatoms selected from thegroup consisting of oxygen, sulfur and nitrogen and optionallysubstituted with one or more alkyl or alkoxy groups.
 23. Thepharmaceutical composition according to claim 22 wherein Y is selectedfrom the group consisting of amino (—NH₂), N-(iso-butyl)amino,N-methylamino, N,N-dimethylamino, and N-benzylamino.
 24. Thepharmaceutical composition according to claim 1 wherein the compound offormula I is selected from the group consisting of:N-[N-(3,4-dichlorophenyl)alanyl]valine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]valine N-iso-butyl amide;N-[N-(3,4-dichlorophenyl)alanyl]threonine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]valine ethyl ester;N-[N-(3,4-dichlorophenyl)alanyl]valine tert-butyl ester;N-[N-(3,4-dichlorophenyl)alanyl]valine amide;N-[N-(3,4-dichlorophenyl)alanyl]valine N,N-dimethyl amide;N-[N-(3,4-dichlorophenyl)alanyl]valine N-methyl amide;N-[N-(3,4-dichiorophenyl)alanyl]alanine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]leucine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]phenylalanine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]isoleucine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]-2-aminopentanoic acid methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]-2-aminohexanoic acid methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]tryptophan methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]aspartic acid α-methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]aspartic acid β-(tert-butyl ester)α-methyl ester; N-[N-(3,4-dichlorophenyl)alanyl]-N-BOC-lysine methylester; N-[N-benzothiazol-6-yl)alanyl]-2-aminohexanoic acid methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]lysine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]tyrosine methyl ester;N-[N-(3,5-dichlorophenyl)alanyl]alanine methyl ester;N-[N-(3,5-dichlorophenyl)alanyl]-2-aminopentanoic acid methyl ester;N-[N-(3,5-dichlorophenyl)alanyl]phenylalanine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]aspartic acid β-(methyl ester) α-methylester; N-[N-(3,4-dichlorophenyl)alanyl]-1-benzylhistidine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]glutamic acid γ-(tert-butyl ester)α-methyl ester; N-[N-(3,4-dichlorophenyl)alanyl]leucine amide;N-[N-(3,4-dichlorophenyl)alanyl]glutamic acid α-methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]-(3,5-diiodo)tyrosine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]-(3-iodo)tyrosine methyl ester;N-[N-(3,5-dichlorophenyl)glycyl]-2-aminopentanoic acid methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]-Nε-(hexanoyl)lysine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]phenylalanine amide;N-[N-(3,4-dichlorophenyl)alanyl]-2-aminohexan-(N-methyl)-amide;N-[N-(3,4-dichlorophenyl)alanyl]β-cyclohexylalanine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]-2-aminohexanamide;N-[N-(3,4-dichlorophenyl)alanyl]-2-aminohexan-(N,N-dimethyl)-amide;N-[N-(3,4-dichlorophenyl)alanyl]methionine methyl ester;N-[N-(3,5-dichlorophenyl)alanyl]-2-aminohexan-(N,N-dimethyl)-amide;N-[N-(3,5-dichlorophenyl)alanyl]-2-aminohexanamide;N-[N-(3,5-dichlorophenyl)alanyl]-2-aminohexan-(N-methyl)-amide;N-[N-(3,4-dichlorophenyl)alanyl]histidine methyl ester;N-[N-(quinolin-3-yl)alanyl]-2-aminohexanoic acid methyl ester;N-[N-(benzothiazol-2-yl)-L-alanyl]-2-aminohexanoic acid methyl ester;N-[N-(3,5-difluorophenyl)alanyl]alanine methyl ester;N-[N-(3,5-difluorophenyl)alanyl]-2-aminohexanoic acid methyl ester;N-[N-(3,4-dichlorophenyl)-L-alanyl]-S-2-aminohexanamide;N-[N-(3,4-dichlorophenyl)alanyl]-2-aminohexan-(N-benzyl)-amide;N-[N-(3,5-dichlorophenyl)phenylglycinyl]alanine methyl ester;N-[N-(3,5-dichlorophenyl)-L-alanyl]-L-phenylglycine tert-butyl ester;N-[N-(3,5-di-(trifluoromethyl)phenyl)-L-alanyl]-L-phenylglycinetert-butyl ester; N-[N-(3,5-dimethoxyphenyl)-L-alanyl]-2-aminohexanoicacid methyl ester; and pharmaceutically acceptable salts thereof.
 25. Acompound of formula III:

wherein R¹ is selected from the group consisting of (a) phenyl, (b) asubstituted phenyl group of formula II:

wherein R^(c) is selected from the group consisting of acyl, alkyl,alkoxy, alkylalkoxy, azido, cyano, halo, hydrogen, nitro, trihalomethyl,thioalkoxy, and wherein R^(b) and R^(c) are fused to form a heteroarylor heterocyclic ring with the phenyl ring, R^(b) and R^(b)′ areindependently selected from the group consisting of hydrogen, halo,nitro, cyano, trihalomethyl, alkoxy, and thioalkoxy with the provisothat when R^(c) is hydrogen, then R^(b) and R^(b)′ are either bothhydrogen or both substituents other than hydrogen, (c) 2-naphthyl, (d)2-naphthyl substituted at the 4, 5, 6, 7 and/or 8 positions with 1 to 5substituents selected from the group consisting of alkyl, alkoxy, halo,cyano, nitro, trihalomethyl, thioalkoxy, aryl, and heteroaryl, (e)heteroaryl, and (f) substituted heteroaryl containing 1 to 3substituents selected from the group consisting of alkyl, alkoxy, aryl,aryloxy, cyano, halo, nitro, heteroaryl, thioalkoxy and thioaryloxyprovided that said substituents are not ortho to the heteroarylattachment to the —NH group; R² is selected from the group consisting ofalkyl of from 1 to 4 carbons atoms, alkylalkoxy of from 1 to 4 carbonatoms, alkylthioalkoxy of from 1 to 4 carbon atoms, aryl, heteroaryl,substituted aryl and substituted heteroaryl provided that thesubstituents are not ortho to the attachment of the aryl or heteroarylatom to the carbon atom; R³ is selected from the group consisting ofalkyl, alkenyl, alkynyl, aryl, cycloalkyl, cycloalkenyl, heteroaryl,substituted alkyl, substituted alkenyl, substituted alkynyl, andheterocyclic; X is —C(O)Y where Y is selected from the group consistingof (a) alkyl, (b) substituted alkyl with the proviso that thesubstitution on said substituted alkyl does not include α-haloalkyl,α-diazoalkyl or α-OC(O)alkyl groups, (c) alkoxy or thioalkoxy, (d)substituted alkoxy or substituted thioalkoxy, (e) hydroxy, (f) aryl, (g)heteroaryl, (h) heterocyclic, (i) —NR′R″ where R′ and R″ areindependently selected from the group consisting of: hydrogen, alkyl,substituted alkyl of from 1 to 10 carbon atoms, having from 1 to 3substituents selected from the group consisting of alkoxy, substitutedalkoxy, acyl, acylamino, acyloxy, amino, aminoacyl, aminoacyloxy, cyan,halogen, carboxyl, carboxylalkyl, cycloalkyl, oxyacylamino, thiol,thioalkoxy, substituted thioalkoxy, aryl, heteroaryl, heterocyclic,nitro, and mono- and di-alkylamino, mono- and di-(substitutedalkyl)amino, mono- and di-cycloalkylamino, mono- and di-arylamino, mono-and di-heteroaryl-amino, mono- and di-heterocyclic amino, andunsymmetric di-substituted amines having different substituents selectedfrom alkyl, substituted alkyl, cycloalkyl, aryl, heteroaryl, andheterocyclic, cycloalkyl, aryl, heteroaryl, heterocyclic, and where R′and R″ are joined to form a cyclic group having from 2 to 8 carbon atomsoptionally containing 1 to 2 additional heteroatoms selected from thegroup consisting of oxygen, sulfur and nitrogen and optionallysubstituted with one or more alkyl or alkoxy groups, and when R³contains at least 3 carbon atoms, X can also be —CR⁴R⁴Y′ where each R⁴is independently selected from the group consisting of hydrogen, alkyl,cycloalkyl, aryl, heteroaryl and heterocyclic and Y′ is selected fromthe group consisting of amino, thiol, —OC(O)R⁵, —SSR⁵, —SSC(O)R⁵ whereR⁵ is selected from the group consisting of alkyl, substituted alkyl,cycloalkyl, aryl, heteroaryl and heterocyclic, and with the proviso thatwhen R¹ is 3,4-dichlorophenyl, R² is methyl, and R³ is benzyl derivedfrom D-phenylalanine, then X is not —C(O)OCH₃, and still with thefurther proviso excluding the following known compounds: when R¹ isphenyl, R² is methyl, and X is —C(O)NHφ, then R³ is not methyl,iso-propyl, iso-butyl; when R¹ is phenyl, R² is methyl, and X is—C(O)NH₂, then R³ is not benzyl; and when R¹ is p-chlorophenyl, R² ishydrogen, and X is —C(O)OH, then R³ is not methyl or isobutyl.
 26. Thecompound according to claim 25 wherein R¹ is phenyl, 2-naphthyl,quinolin-3-yl, benzothiazol-6-yl, and 5-indolyl.
 27. The compoundaccording to claim 25 wherein R¹ is a substituted phenyl group of theformula:

wherein R^(c) is selected from the group consisting of acyl, alkyl,alkoxy, alkylalkoxy, azido, cyano, halo, hydrogen, nitro, trihalomethyl,thioalkoxy, and wherein R^(b) and R^(c) are fused to form a heteroarylor heterocyclic ring with the phenyl ring, R^(b) and R^(b′) areindependently selected from the group consisting of hydrogen, halo,nitro, cyano, trihalomethyl, alkoxy, and thioalkoxy with the provisothat when R^(c) is hydrogen, then R^(b) and R^(b′) are either bothhydrogen or both substituents other than hydrogen.
 28. The compoundaccording to claim 25 wherein R¹ is a substituted 2-naphthyl substitutedat the 4, 5, 6, 7 and/or 8 positions with 1 to 5 substituents selectedfrom the group consisting of alkyl, alkoxy, halo, cyano, nitro,trihalomethyl, thioalkoxy, aryl, and heteroaryl.
 29. The compoundaccording to claim 25 wherein R¹ is a substituted heteroaryl containing1 to 3 substituents selected from the group consisting of alkyl, alkoxy,aryl, aryloxy, cyano, halo, nitro, heteroaryl, thioalkoxy, thioaryloxyprovided that said substituents are not ortho to the heteroarylattachment to the —NH group.
 30. The compound according to claim 29wherein R¹ is a 4-substituted, a 3,5-disubstituted or 3,4-disubstitutedphenyl.
 31. The compound according to claim 30 wherein R¹ is a3,5-disubstituted phenyl.
 32. The compound according to claim 31 whereinthe 3,5-disubstituted phenyl is selected from the group consisting of3,5-dichlorophenyl, 3,5-difluorophenyl, 3,5-di(trifluoromethyl)phenyland 3,5-dimethoxyphenyl.
 33. The compound according to claim 30 whereinR¹ is a 3,4-disubstituted phenyl.
 34. The compound according to claim 33wherein the 3,4-disubstituted phenyl is selected from the groupconsisting of 3,4-dichlorophenyl, 3,4-difluorophenyl,3-(trifluoromethyl)-4-chlorophenyl, 3-chloro-4-cyanophenyl,3-chloro-4-iodophenyl and 3,4-methylenedioxyphenyl.
 35. The compoundaccording to claim 25 wherein R¹ is a 4-substituted phenyl.
 36. Thecompound according to claim 35 wherein the 4-substituted phenyl isselected from the group consisting of 4-azidophenyl, 4-bromophenyl,4-chlorophenyl, 4-cyanophenyl, 4-ethylphenyl, 4-fluorophenyl,4-iodophenyl, 4-(phenylcarbonyl)phenyl, and 4-(1-ethoxy)ethylphenyl. 37.The compound according to claim 25 wherein R¹ is 2-methyiquinolin-6-yl.38. The compound according to claim 25 wherein R² is selected from thegroup consisting of alkyl of from 1 to 4 carbon atoms, alkylalkoxy offrom 1 to 4 carbon atoms, alkylthioalkoxy of from 1 to 4 carbon atomsand aryl.
 39. The compound according to claim 38 wherein R² is selectedfrom the group consisting of methyl, ethyl, n-propyl, iso-propyl,n-butyl, iso-butyl, —CH₂CH₂SCH₃ and phenyl.
 40. The compound accordingto claim 25 wherein R³ is an alkyl group.
 41. The compound according toclaim 40 wherein the alkyl group is selected from the group consistingof methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl andsec-butyl.
 42. The compound according to claim 25 wherein R³ is asubstituted alkyl group.
 43. The compound according to claim 42 whereinthe substituted alkyl group is selected from the group consisting ofα-hydroxyethyl, —CH₂-cyclohexyl, benzyl, p-hydroxybenzyl,3-iodo-4-hydroxybenzyl, 3,5-diiodo-4-hydroxybenzyl, —CH₂-indol-3-yl,—(CH₂)₄—NH-BOC, —(CH₂)₄—NH₂, —CH₂-( 1-N-benzyl-imidazol-4-yl),—CH₂-imidazol-4-yl, —CH₂CH₂SCH₃, —(CH₂)₄NHC(O)(CH₂)₃CH₃, and—(CH₂)_(y)C(O)OR⁵ where y is 1 or 2 and R⁵ is hydrogen, methyl, ortert-butyl.
 44. The compound according to claim 25 wherein X is —C(O)Ywherein Y is selected from the group consisting of alkoxy andthioalkoxy.
 45. The compound according to claim 44 wherein Y is alkoxyselected from the group consisting of methoxy, ethyoxy, n-propoxy,iso-propoxy, n-butoxy, iso-butoxy, and tert-butoxy.
 46. The compoundaccording to claim 25 wherein X is —C(O)Y and Y is —NR′R″ where R′ andR″ are independently selected from the group consisting of hydrogen,alkyl, substituted alkyl, cycloalkyl, aryl, heteroaryl, heterocyclic,and where R′ and R″ are joined to form a cyclic group having from 2 to 8carbon atoms optionally containing 1 to 2 additional heteroatomsselected from the group consisting of oxygen, sulfur and nitrogen andoptionally substituted with one or more alkyl or alkoxy groups.
 47. Thecompound according to claim 46 wherein Y is selected from the groupconsisting of amino (—NH₂), N-(iso-butyl)amino, N-methylamino,N,N-dimethylamino, and N-benzylamino.
 48. The compound according toclaim 25 wherein the compound of formula III is selected from the groupconsisting of: N-[N-(3,4-dichlorophenyl)alanyl]valine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]valine N-iso-butyl amide;N-[N-(3,4-dichlorophenyl)alanyl]threonine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]valine ethyl ester;N-[N-(3,4-dichlorophenyl)alanyl]valine tert-butyl ester;N-[N-(3,4-dichlorophenyl)alanyl]valine amide;N-[N-(3,4-dichlorophenyl)alanyl]valine N,N-dimethyl amide;N-[N-(3,4-dichlorophenyl)alanyl]valine N-methyl amide;N-[N-(3,4-dichlorophenyl)alanyl]alanine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]leucine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]phenylalanine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]isoleucine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]-2-aminopentanoic acid methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]-2-aminohexanoic acid methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]tryptophan methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]aspartic acid α-methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]aspartic acid β-(tert-butyl ester)α-methyl ester; N-[N-(3,4-dichlorophenyl)alanyl]-N-BOC-lysine methylester; N-[N-benzothiazol-6-yl)alanyl]-2-aminohexanoic acid methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]lysine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]tyrosine methyl ester;N-[N-(3,5-dichlorophenyl)alanyl]alanine methyl ester;N-[N-(3,5-dichlorophenyl)alanyl]-2-aminopentanoic acid methyl ester;N-[N-(3,5-dichlorophenyl)alanyl]phenylalanine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]aspartic acid β-(methyl ester) α-methylester; N-[N-(3,4-dichlorophenyl)alanyl]1-benzylhistidine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]glutamic acid γ-(tert-butyl ester)α-methyl ester; N-[N-(3,4-dichlorophenyl)alanyl]leucine amide;N-[N-(3,4-dichlorophenyl)alanyl]glutamic acid α-methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]-(3,5-diiodo)tyrosine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]-(3-iodo)tyrosine methyl ester;N-[N-(3,5-dichlorophenyl)glycyl]-2-aminopentanoic acid methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]-Nε-(hexanoyl)lysine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]phenylalanine amide;N-[N-(3,4-dichlorophenyl)alanyl]-2-aminohexan-(N-methyl)-amide;N-[N-(3,4-dichlorophenyl)alanyl]-β-cyclohexylalanine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]-2-aminohexanamide;N-[N-(3,4-dichlorophenyl)alanyl]-2-aminohexan-(N,N-dimethyl)-amide;N-[N-(3,4-dichlorophenyl)alanyl]methionine methyl ester;N-[N-(3,5-dichlorophenyl)alanyl]-2-aminohexan-(N,N-dimethyl)-amide;N-[N-(3,5-dichlorophenyl)alanyl]-2-aminohexanamide;N-[N-(3,5-dichlorophenyl)alanyl]-2-aminohexan-(N-methyl)-amide;N-[N-(3,4-dichlorophenyl)alanyl]histidine methyl ester;N-[N-(quinolin-3-yl)alanyl]-2-aminohexanoic acid methyl ester;N-[N-(benzothiazol-2-yl)-L-alanyl]-2-aminohexanoic acid methyl ester;N-[N-(3,5-difluorophenyl)alanyl]alanine methyl ester;N-[N-(3,5-difluorophenyl)alanyl]-2-aminohexanoic acid methyl ester;N-[N-(3,4-dichlorophenyl)-L-alanyl]-S-2-aminohexanamide;N-[N-(3,4-dichlorophenyl)alanyl]-2-aminohexan-(N-benzyl)-amide;N-[N-(3,5-dichlorophenyl)phenylglycinyl]alanine methyl ester;N-[N-(3,5-dichlorophenyl)-L-alanyl]-L-phenylglycine tert-butyl ester;N-[N-(3,5-di-(trifluoromethyl)phenyl)-L-alanyl]-L-phenylglycinetert-butyl ester; N-[N-(3,5-dimethoxyphenyl)-L-alanyl]-2-aminohexanoicacid methyl ester; and pharmaceutically acceptable salts thereof.
 49. Acompound of formula III:

wherein: R¹ is selected from the group consisting of (a) phenyl, (b) asubstituted phenyl group of formula II:

wherein R^(c) is selected from the group consisting of acyl, alkyl,alkoxy, alkylalkoxy, azido, cyano, halo, hydrogen, nitro, trihalomethyl,thioalkoxy, and wherein R^(b) and R^(c) are fused to form a heteroarylor heterocyclic ring with the phenyl ring, R^(b) and R^(b′) areindependently selected from the group consisting of hydrogen, halo,nitro, cyano, trihalomethyl, alkoxy, and thioalkoxy with the provisothat when R^(c) is hydrogen, then R^(b) and R^(b′) are either bothhydrogen or both substituents other than hydrogen, (c) 2-naphthyl, (d)2-naphthyl substituted at the 4, 5, 6, 7 and/or 8 positions with 1 to 5substituents selected from the group consisting of alkyl, alkoxy, halo,cyano, nitro, trihalomethyl, thioalkoxy, aryl, and heteroaryl, (e)heteroaryl, and (f) substituted heteroaryl containing 1 to 3substituents selected from the group consisting of alkyl, alkoxy, aryl,aryloxy, cyano, halo, nitro, heteroaryl, thioalkoxy and thioaryloxyprovided that said substituents are not ortho to the heteroarylattachment to the —NH group; R² is selected from the group consisting ofalkyl of from 1 to 4 carbon atoms, alkylalkoxy of from 1 to 4 carbonatoms, alkylthioalkoxy of from 1 to 4 carbon atoms, aryl, heteroaryl,substituted aryl and substituted heteroaryl provided that thesubstituents are not ortho to the attachment of the aryl or heteroarylatom to the carbon atom; R³ is selected from the group consisting ofalkyl, alkenyl, alkynyl, aryl, cycloalkyl, cycloalkenyl, heteroaryl,substituted alkyl, substituted alkenyl, substituted alkynyl, andheterocyclic; X is —C(O)Y where Y is selected from the group consistingof (a) alkyl, (b) substituted alkyl with the proviso that thesubstitution on said substituted alkyl does not include α-haloalkyl,α-diazoalkyl or α-OC(O)alkyl groups, (c) alkoxy or thioalkoxy, (d)substituted alkoxy or substituted thioalkoxy, (e) hydroxy, (f) aryl, (g)heteroaryl, (h) heterocyclic, (i) —NR′R″ where R′ and R″ areindependently selected from the group consisting of: hydrogen, alkyl,substituted alkyl of from 1 to 10 carbon atoms, having from 1 to 3substituents selected from the group consisting of alkoxy, substitutedalkoxy, acyl, acylamino, acyloxy, amino, aminoacyl, aminoacyloxy, cyano,halogen, carboxyl, carboxylalkyl, cycloalkyl, oxyacylamino, thiol,thioalkoxy, substituted thioalkoxy, aryl, heteroaryl, heterocyclic,nitro, and mono- and di-alkylamino, mono- and di-(substitutedalkyl)amino, mono- and di-cycloalkylamino, mono- and di-arylamino, mono-and di-heteroaryl-amino, mono- and di-heterocyclic amino, andunsymmetric di-substituted amines having different substituents selectedfrom alkyl, substituted alkyl, cycloalkyl, aryl, heteroaryl andheterocyclic, cycloalkyl, aryl, heteroaryl, heterocyclic, and where R′and R″ are joined to form a cyclic group having from 2 to 8 carbon atomsoptionally containing 1 to 2 additional heteroatoms selected from thegroup consisting of oxygen, sulfur and nitrogen and optionallysubstituted with one or more alkyl or alkoxy groups, and when R³contains at least 3 carbon atoms, X can also be —CR⁴R⁴Y′ where each R⁴is independently selected from the group consisting of hydrogen, alkyl,cycloalkyl, aryl, heteroaryl and heterocyclic and Y′ is selected fromthe group consisting of amino, thiol, —OC(O)R⁵, —SSR⁵, —SSC(O)R⁵ whereR⁵ is selected from the group consisting of alkyl, substituted alkyl,cycloalkyl, aryl, heteroaryl and heterocyclic, and with the proviso thatwhen R¹ is 3,4-dichlorophenyl, R² is methyl, and R³ is benzyl derivedfrom D-phenylalanine, then X is not —C(O)OCH₃, and still with thefurther proviso excluding the following known compounds: when R¹ isphenyl, R² is methyl, and X is —C(O)NHφ, then R³ is not methyl,iso-propyl, iso-butyl; and when R¹ is phenyl, R² is methyl, and X is—C(O)NH₂, then R³ is not benzyl.
 50. The compound according to claim 49wherein R¹ is phenyl, 2-naphthyl, quinolin-3-yl, benzothiazol-6-yl, and5-indolyl.
 51. The compound according to claim 49 wherein R¹ is asubstituted phenyl group of the formula:

wherein R^(c) is selected from the group consisting of acyl, alkyl,alkoxy, alkylalkoxy, azido, cyano, halo, hydrogen, nitro,trihalomethlyl, thioalkoxy, and wherein R^(b) and R^(c) are fused toform a heteroaryl or heterocyclic ring with the phenyl ring, R^(b) andR^(b′) are independently selected from the group consisting of hydrogen,halo, nitro, cyano, trihalomethyl, alkoxy, and thioalkoxy with theproviso that when R^(c) is hydrogen, then R^(b) and R^(b′) are eitherboth hydrogen or both substituents other than hydrogen.
 52. The compoundaccording to claim 49 wherein R¹ is a substituted 2-naphthyl substitutedat the 4, 5, 6, 7 and/or 8 positions with 1 to 5 substituents selectedfrom the group consisting of alkyl, alkoxy, halo, cyano, nitro,trihalomethyl, thioalkoxy, aryl, and heteroaryl.
 53. The compoundaccording to claim 49 wherein R¹ is a substituted heteroaryl containing1 to 3 substituents selected from the group consisting of alkyl, alkoxy,aryl, aryloxy, cyano, halo, nitro, heteroaryl, thioalkoxy, thioaryloxyprovided that said substituents are not ortho to the heteroarylattachment to the —NH group.
 54. The compound according to claim 53wherein R¹ is a 4-substituted, a 3,5-disubstituted or 3,4-disubstitutedphenyl.
 55. The compound according to claim 54 wherein R¹ is a3,5-disubstituted phenyl.
 56. The compound according to claim 55 whereinthe 3,5-disubstituted phenyl is selected from the group consisting of3,5-dichlorophenyl, 3,5-difluorophenyl, 3,5-di(trifluoromethyl)phenyland 3,5-dimethoxyphenyl.
 57. The compound according to claim 54 whereinR¹ is a 3,4-disubstituted phenyl.
 58. The compound according to claim 57wherein the 3,4-disubstituted phenyl is selected from the groupconsisting of 3,4-dichlorophenyl, 3,4-difluorophenyl,3-(trifluoromethyl)-4-chlorophenyl, 3-chloro-4-cyanophenyl,3-chloro-4-iodophenyl and 3,4-methylenedioxyphenyl.
 59. The compoundaccording to claim 54 wherein R¹ is a 4-substituted phenyl.
 60. Thecompound according to claim 59 wherein the 4-substituted phenyl isselected from the group consisting of 4-azidophenyl, 4-bromophenyl,4-chlorophenyl, 4-cyanophenyl, 4-ethylphenyl, 4-fluorophenyl,4-iodophenyl, 4-(phenylcarbonyl)phenyl, and 4-(1 -ethoxy)ethylphenyl.61. The compound according to claim 49 wherein R¹ is2-methylquinolin-6-yl.
 62. The compound according to claim 49 wherein R²is selected from the group consisting of alkyl of from 1 to 4 carbonatoms, alkylalkoxy of from 1 to 4 carbon atoms, alkylthioalkoxy of from1 to 4 carbon atoms and aryl.
 63. The compound according to claim 62wherein R² is selected from the group consisting of methyl, ethyl,n-propyl, iso-propyl, n-butyl, iso-butyl, —CH₂CH₂SCH₃ and phenyl. 64.The compound according to claim 49 wherein R³ is an alkyl group.
 65. Thecompound according to claim 64 wherein the alkyl group is selected fromthe group consisting of methyl, ethyl, n-propyl, iso-propyl, n-butyl,iso-butyl and sec-butyl.
 66. The compound according to claim 49 whereinR³ is a substituted alkyl group.
 67. The compound according to claim 66wherein the substituted alkyl group is selected from the groupconsisting of α-hydroxyethyl, —CH₂-cyclohexyl, benzyl, p-hydroxybenzyl,3-iodo-4-hydroxybenzyl, 3,5-diiodo-4-hydroxybenzyl, —CH₂-indol-3-yl,—(CH₂)₄—NH-BOC, —(CH₂)₄—NH₂, —CH₂-(1-N-benzyl-imidazol-4-yl),—CH₂-imidazol-4-yl, —CH₂CH₂SCH₃, —(CH₂)₄NHC(O)(CH₂)₃CH₃, and—(CH₂)_(y)C(O)OR⁵ where y is 1 or 2 and R⁵ is hydrogen, methyl, ortert-butyl.
 68. The compound according to claim 49 wherein X is —C(O)Ywherein Y is selected from the group consisting of alkoxy andthioalkoxy.
 69. The compound according to claim 68 wherein Y is alkoxyselected from the group consisting of methoxy, ethyoxy, n-propoxy,iso-propoxy, n-butoxy, iso-butoxy, and tert-butoxy.
 70. The compoundaccording to claim 49 wherein X is —C(O)Y and Y is —NR′R″ where R′ andR″ are independently selected from the group consisting of hydrogen,alkyl, substituted alkyl, cycloalkyl, aryl, heteroaryl, heterocyclic,and where R′ and R″ are joined to form a cyclic group having from 2 to 8carbon atoms optionally containing 1 to 2 additional heteroatomsselected from the group consisting of oxygen, sulfur and nitrogen andoptionally substituted with one or more alkyl or alkoxy groups.
 71. Thecompound according to claim 70 wherein Y is selected from the groupconsisting of amino (—NH₂), N-(iso-butyl)amino, N-methylamino,N,N-dimethylamino, and N-benzylamino.
 72. The compound according toclaim 49 wherein the compound of formula III is selected from the groupconsisting of: N-[N-(3,4-dichlorophenyl)alanyl]valine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]valine N-iso-butyl amide;N-[N-(3,4-dichlorophenyl)alanyl]threonine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]valine ethyl ester;N-[N-(3,4-dichlorophenyl)alanyl]valine tert-butyl ester;N-[N-(3,4-dichlorophenyl)alanyl]valine amide;N-[N-(3,4-dichlorophenyl)alanyl]valine N,N-dimethyl amide;N-[N-(3,4-dichlorophenyl)alanyl]valine N-methyl amide;N-[N-(3,4-dichlorophenyl)alanyl]alanine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]leucine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]phenylalanine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]isoleucine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]-2-aminopentanoic acid methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]-2-aminohexanoic acid methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]tryptophan methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]aspartic acid α-methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]aspartic acid β-(tert-butyl ester)α-methyl ester; N-[N-(3,4-dichlorophenyl)alanyl]-N-BOC-lysine methylester; N-[N-benzothiazol-6-yl)alanyl]-2-aminohexanoic acid methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]lysine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]tyrosine methyl ester;N-[N-(3,5-dichlorophenyl)alanyl]alanine methyl ester;N-[N-(3,5-dichlorophenyl)alanyl]-2-aminopentanoic acid methyl ester;N-[N-(3,5-dichlorophenyl)alanyl]phenylalanine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]aspartic acid β-(methyl ester) α-methylester; N-[N-(3,4-dichlorophenyl)alanyl]-1-benzylhistidine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]glutamic acid γ-(tert-butyl ester)α-methyl ester; N-[N-(3,4-dichlorophenyl)alanyl]leucine amide;N-[N-(3,4-dichlorophenyl)alanyl]glutamic acid α-methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]-(3,5-diiodo)tyrosine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]-(3-iodo)tyrosine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]-Nε-(hexanoyl)lysine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]phenylalanine amide;N-[N-(3,4-dichlorophenyl)alanyl]-2-aminohexan-(N-methyl)-amide;N-[N-(3,4-dichlorophenyl)alanyl]-β-cyclohexylalanine methyl ester;N-[N-(3,4-dichlorophenyl)alanyl]-2-aminohexanamide;N-[N-(3,4-dichlorophenyl)alanyl]-2-aminohexan-(N,N-dimethyl)-amide;N-[N-(3,4-dichlorophenyl)alanyl]methionine methyl ester;N-[N-(3,5-dichlorophenyl)alanyl]-2-aminohexan-(N,N-dimethyl)-amide;N-[N-(3,5-dichlorophenyl)alanyl]-2-aminohexanamide;N-[N-(3,5-dichlorophenyl)alanyl]-2-aminohexan-(N-methyl)-amide;N-[N-(3,4-dichlorophenyl)alanyl]histidine methyl ester;N-[N-(quinolin-3-yl)alanyl]-2-aminohexanoic acid methyl ester;N-[N-(benzothiazol-2-yl)-L-alanyl]-2-amiaohexanoic acid methyl ester;N-[N-(3,5-difluorophenyl)alanyl]alanine methyl ester;N-[N-(3,5-difluorophenyl)alanyl]-2-aminohexanoic acid methyl ester;N-[N-(3,4-dichlorophenyl)-L-alanyl]-S-2-aminohexanamide;N-[N-(3,4-dichlorophenyl)alanyl]-2-aminohexan-(N-benzyl)-amide;N-[N-(3,5-dichlorophenyl)-L-alanyl]-L-phenylglycine tert-butyl ester;N-[N-(3,5-di-(trifluoromethyl)phenyl)-L-alanyl]-L-phenylglycinetert-butyl ester; N-[N-(3,5-dimethoxyphenyl)-L-alanyl]-2-aminohexanoicacid methyl ester; and pharmaceutically acceptable salts thereof.